Apparatus for transmitting broadcast signals, apparatus for receiving broadcast signals, method for transmitting broadcast signals and method for receiving broadcast signals

ABSTRACT

The present invention provides a method of transmitting broadcast signals. The method includes, encoding Data Pipe, DP, data according to a code rate, wherein the encoding further includes Low-Density Parity-Check, LDPC, encoding the DP data, Bit interleaving the LDPC encoded DP data, and mapping the bit interleaved DP data onto constellations; building at least one signal frame by mapping the encoded DP data; and modulating data in the built signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, method and transmitting the broadcast signals having the modulated data.

TECHNICAL FIELD

The present invention relates to an apparatus for transmitting broadcastsignals, an apparatus for receiving broadcast signals and methods fortransmitting and receiving broadcast signals.

BACKGROUND ART

As analog broadcast signal transmission comes to an end, varioustechnologies for transmitting/receiving digital broadcast signals arebeing developed. A digital broadcast signal may include a larger amountof video/audio data than an analog broadcast signal and further includevarious types of additional data in addition to the video/audio data.

That is, a digital broadcast system can provide HD (high definition)images, multichannel audio and various additional services. However,data transmission efficiency for transmission of large amounts of data,robustness of transmission/reception networks and network flexibility inconsideration of mobile reception equipment need to be improved fordigital broadcast.

DISCLOSURE OF INVENTION Technical Problem

An object of the present invention is to provide an apparatus and methodfor transmitting broadcast signals to multiplex data of a broadcasttransmission/reception system providing two or more different broadcastservices in a time domain and transmit the multiplexed data through thesame RF signal bandwidth and an apparatus and method for receivingbroadcast signals corresponding thereto.

Another object of the present invention is to provide an apparatus fortransmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals toclassify data corresponding to services by components, transmit datacorresponding to each component as a data pipe, receive and process thedata

Still another object of the present invention is to provide an apparatusfor transmitting broadcast signals, an apparatus for receiving broadcastsignals and methods for transmitting and receiving broadcast signals tosignal signaling information necessary to provide broadcast signals.

Solution to Problem

To achieve the object and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, thepresent invention provides a method of transmitting broadcast signals.The method of transmitting broadcast signals includes encoding DataPipe, DP, data according to a code rate, wherein the encoding furtherincludes Low-Density Parity-Check, LDPC, encoding the DP data usingaddresses of a parity check matrix and length of a LDPC codeword,wherein the addresses of the parity check matrix indicates addresses ofparity bits to be calculated, wherein the addresses of the parity checkmatrix is defined according to the code rate, Bit interleaving the LDPCencoded DP data, and mapping the bit interleaved DP data ontoconstellations;

building at least one signal frame by mapping the encoded DP data; andmodulating data in the built signal frame by an Orthogonal FrequencyDivision Multiplexing, OFDM, method and transmitting the broadcastsignals having the modulated data, wherein the signal frame includes anEmergency Alert System, EAS, information for emergency alert, whereinthe signal frame includes a preamble generated by using an EAS sequence,wherein the EAS sequence is to be detected by a receiver for emergencyalert.

Preferably, the code rate is 11/15, wherein the length of the LDPCcodeword is 16200 bits.

Preferably, the parity check matrix includes an information partcorresponding to information bits of the LDPC codeword and a parity partcorresponding to the parity bits of the LDPC codeword, wherein theaddresses of the parity check matrix is expressed as

49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401,

wherein each row represents a first information bit in each group of 360information bits, wherein each value corresponding to the each rowrepresents the addresses of the parity bits to be calculated.

Preferably, each of first to seventh rows has 12 addresses of the paritybits, and each of eighth to thirty-third rows has 3 addresses of theparity bits.

Preferably, the signal frame includes signaling information to decodethe EAS information.

Preferably, the signaling information is included in Emergency AlertChannel, EAC, and wherein the signal frame includes a EAC flagindicating whether the EAC is within the signal frame.

In other aspect, the present invention provides a method of receivingbroadcast signals. The method of receiving broadcast signals includesreceiving broadcast signals having modulated data in signal frames andde-modulating the modulated data by an Orthogonal Frequency DivisionMultiplexing, OFDM, method; parsing at least one signal frame byde-mapping Data Pipe, DP, data; decoding the DP data according to a coderate, wherein the decoding further includes de-mapping the DP data fromconstellations, Bit de-interleaving the de-mapped DP data, andLow-Density Parity-Check, LDPC, decoding the bit de-interleaved DP datausing addresses of a parity check matrix and length of a LDPC codeword,wherein the addresses of the parity check matrix indicates addresses ofparity bits to be calculated, wherein the addresses of the parity checkmatrix is defined according to the code rate;

wherein the signal frame includes an Emergency Alert System, EAS,information for emergency alert, wherein the signal frame includes apreamble generated by using an EAS sequence, wherein the EAS sequence isto be detected by a receiver for emergency alert.

Preferably, the code rate is 11/15, wherein the length of the LDPCcodeword is 16200 bits.

Preferably, the parity check matrix includes an information partcorresponding to information bits of the LDPC codeword and a parity partcorresponding to the parity bits of the LDPC codeword, wherein theaddresses of the parity check matrix is expressed as

49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401,

wherein each row represents a first information bit in each group of 360information bits, wherein each value corresponding to the each rowrepresents the addresses of the parity bits to be calculated.

Preferably, each of first to seventh rows has 12 addresses of the paritybits, and each of eighth to thirty-third rows has 3 addresses of theparity bits.

Preferably, the signal frame includes signaling information to decodethe EAS information.

Preferably, the signaling information is included in Emergency AlertChannel, EAC, and wherein the signal frame includes a EAC flagindicating whether the EAC is within the signal frame.

In another aspect, the present invention provides an apparatus fortransmitting broadcast signals. The apparatus for transmitting broadcastsignals includes an encoding module configured to encode Data Pipe, DP,data according to a code rate, wherein the encoding module includes aLow-Density Parity-Check, LDPC, encoding module configured to LDPCencode the DP data using addresses of a parity check matrix and lengthof a LDPC codeword, wherein the addresses of the parity check matrixindicates addresses of parity bits to be calculated, wherein theaddresses of the parity check matrix is defined according to the coderate, a Bit interleaving module configured to bit interleave the LDPCencoded DP data, and a mapping module configured to map the bitinterleaved DP data onto constellations; a frame building moduleconfigured to build at least one signal frame by mapping the encoded DPdata; a modulating module configured to modulate data in the builtsignal frame by an Orthogonal Frequency Division Multiplexing, OFDM,method; and a transmitting module configured to transmit the broadcastsignals having the modulated data, wherein the signal frame includes anEmergency Alert System, EAS, information for emergency alert, whereinthe signal frame includes a preamble generated by using an EAS sequence,wherein the EAS sequence is to be detected by a receiver for emergencyalert.

Preferably, the code rate is 11/15, wherein the length of the LDPCcodeword is 16200 bits.

Preferably, the parity check matrix includes an information partcorresponding to information bits of the LDPC codeword and a parity partcorresponding to the parity bits of the LDPC codeword, wherein theaddresses of the parity check matrix is expressed as

49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401,

wherein each row represents a first information bit in each group of 360information bits, wherein each value corresponding to the each rowrepresents the addresses of the parity bits to be calculated.

Preferably, each of first to seventh rows has 12 addresses of the paritybits, and each of eighth to thirty-third rows has 3 addresses of theparity bits.

Preferably, the signal frame includes signaling information to decodethe EAS information.

Preferably, the signaling information is included in Emergency AlertChannel, EAC, and wherein the signal frame includes a EAC flagindicating whether the EAC is within the signal frame.

In another aspect, the present invention provides an apparatus forreceiving broadcast signals. The apparatus for receiving broadcastsignals includes a receiving module configured to receive broadcastsignals having modulated data in signal frames; a de-modulating moduleconfigured to de-modulate the modulated data by an Orthogonal FrequencyDivision Multiplexing, OFDM, method; a parsing module configured toparse at least one signal frame by de-mapping Data Pipe, DP, data; adecoding module configured to decode the DP data according to a coderate, wherein the decoding module includes a de-mapping moduleconfigured to de-map the DP data from constellations, a Bitde-interleaving module configured to bit de-interleave the de-mapped DPdata, and a Low-Density Parity-Check, LDPC, decoding module configuredto LDPC decode the bit de-interleaved DP data using addresses of aparity check matrix and length of a LDPC codeword, wherein the addressesof the parity check matrix indicates addresses of parity bits to becalculated, wherein the addresses of the parity check matrix is definedaccording to the code rate; wherein the signal frame includes anEmergency Alert System, EAS, information for emergency alert, whereinthe signal frame includes a preamble generated by using an EAS sequence,wherein the EAS sequence is to be detected by a receiver for emergencyalert.

Preferably, the code rate is 11/15, wherein the length of the LDPCcodeword is 16200 bits.

Preferably, the parity check matrix includes an information partcorresponding to information bits of the LDPC codeword and a parity partcorresponding to the parity bits of the LDPC codeword, wherein theaddresses of the parity check matrix is expressed as

49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401,

wherein each row represents a first information bit in each group of 360information bits, wherein each value corresponding to the each rowrepresents the addresses of the parity bits to be calculated.

Preferably, each of first to seventh rows has 12 addresses of the paritybits, and each of eighth to thirty-third rows has 3 addresses of theparity bits.

Preferably, the signal frame includes signaling information to decodethe EAS information.

Preferably, the signaling information is included in Emergency AlertChannel, EAC, and wherein the signal frame includes a EAC flagindicating whether the EAC is within the signal frame.

Advantageous Effects of Invention

The present invention can process data according to servicecharacteristics to control QoS (Quality of Services) for each service orservice component, thereby providing various broadcast services.

The present invention can achieve transmission flexibility bytransmitting various broadcast services through the same RF signalbandwidth.

The present invention can improve data transmission efficiency andincrease robustness of transmission/reception of broadcast signals usinga MIMO system.

According to the present invention, it is possible to provide broadcastsignal transmission and reception methods and apparatus capable ofreceiving digital broadcast signals without error even with mobilereception equipment or in an indoor environment.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

FIG. 26 shows a parity check matrix of a QC-IRA (quasi-cyclic irregularrepeat accumulate) LDPC code.

FIG. 27 shows a process of encoding the QC-IRA LDPC code according to anembodiment of the present invention.

FIG. 28 illustrates a parity check matrix permutation process accordingto an embodiment of the present invention.

FIG. 29 is a table showing addresses of parity check matrix according toan embodiment of the present invention.

FIG. 30 is a table showing addresses of parity check matrix according toanother embodiment of the present invention.

FIG. 31 illustrates a method for sequentially encoding the QC-IRA LDPCcode according to an embodiment of the present invention.

FIG. 32 illustrates an LDPC decoder according to an embodiment of thepresent invention.

FIG. 33 illustrates frame structure with EAC according to an embodimentof the present invention.

FIG. 34 illustrates frame structure with EAC according to an embodimentof the present invention.

FIG. 35 illustrates receiver flow for responding to the wake-upindicator according to an embodiment of the present invention.

FIG. 36 illustrates receiver flow for wake-up versioning according to anembodiment of the present invention.

FIG. 37 illustrates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

FIG. 38 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

FIG. 39 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

FIG. 40 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

FIG. 41 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 42 illustrates one of the embodiments of the H₁ matrix according toa code rate of 11/15.

FIG. 43 illustrates one of the embodiments of the H₂ matrix according toa code rate of 11/15.

FIG. 44 illustrates one of the embodiments of the degree distributiontable according to a code rate of 11/15.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. The detailed description, which will be given below withreference to the accompanying drawings, is intended to explain exemplaryembodiments of the present invention, rather than to show the onlyembodiments that can be implemented according to the present invention.The following detailed description includes specific details in order toprovide a thorough understanding of the present invention. However, itwill be apparent to those skilled in the art that the present inventionmay be practiced without such specific details.

Although most terms used in the present invention have been selectedfrom general ones widely used in the art, some terms have beenarbitrarily selected by the applicant and their meanings are explainedin detail in the following description as needed. Thus, the presentinvention should be understood based upon the intended meanings of theterms rather than their simple names or meanings.

The present invention provides apparatuses and methods for transmittingand receiving broadcast signals for future broadcast services. Futurebroadcast services according to an embodiment of the present inventioninclude a terrestrial broadcast service, a mobile broadcast service, aUHDTV service, etc. The present invention may process broadcast signalsfor the future broadcast services through non-MIMO (Multiple InputMultiple Output) or MIMO according to one embodiment. A non-MIMO schemeaccording to an embodiment of the present invention may include a MISO(Multiple Input Single Output) scheme, a SISO (Single Input SingleOutput) scheme, etc.

While MISO or MIMO uses two antennas in the following for convenience ofdescription, the present invention is applicable to systems using two ormore antennas.

The present invention may defines three physical layer (PL) profiles(base, handheld and advanced profiles) each optimized to minimizereceiver complexity while attaining the performance required for aparticular use case. The physical layer (PHY) profiles are subsets ofall configurations that a corresponding receiver should implement.

The three PHY profiles share most of the functional blocks but differslightly in specific blocks and/or parameters. Additional PHY profilescan be defined in the future. For the system evolution, future profilescan also be multiplexed with the existing profiles in a single RFchannel through a future extension frame (FEF). The details of each PHYprofile are described below.

1. Base Profile

The base profile represents a main use case for fixed receiving devicesthat are usually connected to a roof-top antenna. The base profile alsoincludes portable devices that could be transported to a place butbelong to a relatively stationary reception category. Use of the baseprofile could be extended to handheld devices or even vehicular by someimproved implementations, but those use cases are not expected for thebase profile receiver operation.

Target SNR range of reception is from approximately 10 to 20 dB, whichincludes the 15 dB SNR reception capability of the existing broadcastsystem (e.g. ATSC A/53). The receiver complexity and power consumptionis not as critical as in the battery-operated handheld devices, whichwill use the handheld profile. Key system parameters for the baseprofile are listed in below table 1.

TABLE 1 LDPC codeword length 16K, 64K bits Constellation size 4~10 bpcu(bits per channel use) Time de-interleaving memory size ≦2¹⁹ data cellsPilot patterns Pilot pattern for fixed reception FFT size 16K, 32Kpoints

2. Handheld Profile

The handheld profile is designed for use in handheld and vehiculardevices that operate with battery power. The devices can be moving withpedestrian or vehicle speed. The power consumption as well as thereceiver complexity is very important for the implementation of thedevices of the handheld profile. The target SNR range of the handheldprofile is approximately 0 to 10 dB, but can be configured to reachbelow 0 dB when intended for deeper indoor reception.

In addition to low SNR capability, resilience to the Doppler Effectcaused by receiver mobility is the most important performance attributeof the handheld profile. Key system parameters for the handheld profileare listed in the below table 2.

TABLE 2 LDPC codeword length 16K bits Constellation size 2~8 bpcu Timede-interleaving memory size ≦2¹⁸ data cells Pilot patterns Pilotpatterns for mobile and indoor reception FFT size 8K, 16K points

3. Advanced Profile

The advanced profile provides highest channel capacity at the cost ofmore implementation complexity. This profile requires using MIMOtransmission and reception, and UHDTV service is a target use case forwhich this profile is specifically designed. The increased capacity canalso be used to allow an increased number of services in a givenbandwidth, e.g., multiple SDTV or HDTV services.

The target SNR range of the advanced profile is approximately 20 to 30dB. MIMO transmission may initially use existing elliptically-polarizedtransmission equipment, with extension to full-power cross-polarizedtransmission in the future. Key system parameters for the advancedprofile are listed in below table 3.

TABLE 3 LDPC codeword length 16K, 64K bits Constellation size 8~12 bpcuTime de-interleaving memory size ≦2¹⁹ data cells Pilot patterns Pilotpattern for fixed reception FFT size 16K, 32K points

In this case, the base profile can be used as a profile for both theterrestrial broadcast service and the mobile broadcast service. That is,the base profile can be used to define a concept of a profile whichincludes the mobile profile. Also, the advanced profile can be dividedadvanced profile for a base profile with MIMO and advanced profile for ahandheld profile with MIMO. Moreover, the three profiles can be changedaccording to intention of the designer.

The following terms and definitions may apply to the present invention.The following terms and definitions can be changed according to design.

auxiliary stream: sequence of cells carrying data of as yet undefinedmodulation and coding, which may be used for future extensions or asrequired by broadcasters or network operators

base data pipe: data pipe that carries service signaling data

baseband frame (or BBFRAME): set of Kbch bits which form the input toone FEC encoding process (BCH and LDPC encoding)

cell: modulation value that is carried by one carrier of the OFDMtransmission

coded block: LDPC-encoded block of PLS1 data or one of the LDPC-encodedblocks of PLS2 data

data pipe: logical channel in the physical layer that carries servicedata or related metadata, which may carry one or multiple service(s) orservice component(s).

data pipe unit: a basic unit for allocating data cells to a DP in aframe.

data symbol: OFDM symbol in a frame which is not a preamble symbol (theframe signaling symbol and frame edge symbol is included in the datasymbol)

DP_ID: this 8 bit field identifies uniquely a DP within the systemidentified by the SYSTEM_ID

dummy cell: cell carrying a pseudorandom value used to fill theremaining capacity not used for PLS signaling, DPs or auxiliary streams

emergency alert channel: part of a frame that carries EAS informationdata

frame: physical layer time slot that starts with a preamble and endswith a frame edge symbol

frame repetition unit: a set of frames belonging to same or differentphysical layer profile including a FEF, which is repeated eight times ina super-frame

fast information channel: a logical channel in a frame that carries themapping information between a service and the corresponding base DP

FECBLOCK: set of LDPC-encoded bits of a DP data

FFT size: nominal FFT size used for a particular mode, equal to theactive symbol period Ts expressed in cycles of the elementary period T

frame signaling symbol: OFDM symbol with higher pilot density used atthe start of a frame in certain combinations of FFT size, guard intervaland scattered pilot pattern, which carries a part of the PLS data

frame edge symbol: OFDM symbol with higher pilot density used at the endof a frame in certain combinations of FFT size, guard interval andscattered pilot pattern

frame-group: the set of all the frames having the same PHY profile typein a super-frame.

future extension frame: physical layer time slot within the super-framethat could be used for future extension, which starts with a preamble

Futurecast UTB system: proposed physical layer broadcasting system, ofwhich the input is one or more MPEG2-TS or IP or general stream(s) andof which the output is an RF signal

input stream: A stream of data for an ensemble of services delivered tothe end users by the system.

normal data symbol: data symbol excluding the frame signaling symbol andthe frame edge symbol

PHY profile: subset of all configurations that a corresponding receivershould implement

PLS: physical layer signaling data consisting of PLS1 and PLS2

PLS1: a first set of PLS data carried in the FSS symbols having a fixedsize, coding and modulation, which carries basic information about thesystem as well as the parameters needed to decode the PLS2

NOTE: PLS1 data remains constant for the duration of a frame-group.

PLS2: a second set of PLS data transmitted in the FSS symbol, whichcarries more detailed PLS data about the system and the DPs

PLS2 dynamic data: PLS2 data that may dynamically change frame-by-frame

PLS2 static data: PLS2 data that remains static for the duration of aframe-group

preamble signaling data: signaling data carried by the preamble symboland used to identify the basic mode of the system

preamble symbol: fixed-length pilot symbol that carries basic PLS dataand is located in the beginning of a frame

NOTE: The preamble symbol is mainly used for fast initial band scan todetect the system signal, its timing, frequency offset, and FFTsize.

reserved for future use: not defined by the present document but may bedefined in future

superframe: set of eight frame repetition units

time interleaving block (TI block): set of cells within which timeinterleaving is carried out, corresponding to one use of the timeinterleaver memory

TI group: unit over which dynamic capacity allocation for a particularDP is carried out, made up of an integer, dynamically varying number ofXFECBLOCKs.

NOTE: The TI group may be mapped directly to one frame or may be mappedto multiple frames. It may contain one or more TI blocks.

Type 1 DP: DP of a frame where all DPs are mapped into the frame in TDMfashion

Type 2 DP: DP of a frame where all DPs are mapped into the frame in FDMfashion

XFECBLOCK: set of Ncells cells carrying all the bits of one LDPCFECBLOCK

FIG. 1 illustrates a structure of an apparatus for transmittingbroadcast signals for future broadcast services according to anembodiment of the present invention.

The apparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can includean input formatting block 1000, a BICM (Bit interleaved coding &modulation) block 1010, a frame structure block 1020, an OFDM(Orthogonal Frequency Division Multiplexing) generation block 1030 and asignaling generation block 1040. A description will be given of theoperation of each module of the apparatus for transmitting broadcastsignals.

IP stream/packets and MPEG2-TS are the main input formats, other streamtypes are handled as General Streams. In addition to these data inputs,Management Information is input to control the scheduling and allocationof the corresponding bandwidth for each input stream. One or multiple TSstream(s), IP stream(s) and/or General Stream(s) inputs aresimultaneously allowed.

The input formatting block 1000 can demultiplex each input stream intoone or multiple data pipe(s), to each of which an independent coding andmodulation is applied. The data pipe (DP) is the basic unit forrobustness control, thereby affecting quality-of-service (QoS). One ormultiple service(s) or service component(s) can be carried by a singleDP. Details of operations of the input formatting block 1000 will bedescribed later.

The data pipe is a logical channel in the physical layer that carriesservice data or related metadata, which may carry one or multipleservice(s) or service component(s).

Also, the data pipe unit: a basic unit for allocating data cells to a DPin a frame.

In the BICM block 1010, parity data is added for error correction andthe encoded bit streams are mapped to complex-value constellationsymbols. The symbols are interleaved across a specific interleavingdepth that is used for the corresponding DP. For the advanced profile,MIMO encoding is performed in the BICM block 1010 and the additionaldata path is added at the output for MIMO transmission. Details ofoperations of the BICM block 1010 will be described later.

The Frame Building block 1020 can map the data cells of the input DPsinto the OFDM symbols within a frame. After mapping, the frequencyinterleaving is used for frequency-domain diversity, especially tocombat frequency-selective fading channels. Details of operations of theFrame Building block 1020 will be described later.

After inserting a preamble at the beginning of each frame, the OFDMGeneration block 1030 can apply conventional OFDM modulation having acyclic prefix as guard interval. For antenna space diversity, adistributed MISO scheme is applied across the transmitters. In addition,a Peak-to-Average Power Reduction (PAPR) scheme is performed in the timedomain. For flexible network planning, this proposal provides a set ofvarious FFT sizes, guard interval lengths and corresponding pilotpatterns. Details of operations of the OFDM Generation block 1030 willbe described later.

The Signaling Generation block 1040 can create physical layer signalinginformation used for the operation of each functional block. Thissignaling information is also transmitted so that the services ofinterest are properly recovered at the receiver side. Details ofoperations of the Signaling Generation block 1040 will be describedlater.

FIGS. 2, 3 and 4 illustrate the input formatting block 1000 according toembodiments of the present invention. A description will be given ofeach figure.

FIG. 2 illustrates an input formatting block according to one embodimentof the present invention. FIG. 2 shows an input formatting module whenthe input signal is a single input stream.

The input formatting block illustrated in FIG. 2 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

The input to the physical layer may be composed of one or multiple datastreams. Each data stream is carried by one DP. The mode adaptationmodules slice the incoming data stream into data fields of the basebandframe (BBF). The system supports three types of input data streams:MPEG2-TS, Internet protocol (IP) and Generic stream (GS). MPEG2-TS ischaracterized by fixed length (188 byte) packets with the first bytebeing a sync-byte (0x47). An IP stream is composed of variable length IPdatagram packets, as signaled within IP packet headers. The systemsupports both IPv4 and IPv6 for the IP stream. GS may be composed ofvariable length packets or constant length packets, signaled withinencapsulation packet headers.

(a) shows a mode adaptation block 2000 and a stream adaptation 2010 forsignal DP and (b) shows a PLS generation block 2020 and a PLS scrambler2030 for generating and processing PLS data. A description will be givenof the operation of each block.

The Input Stream Splitter splits the input TS, IP, GS streams intomultiple service or service component (audio, video, etc.) streams. Themode adaptation module 2010 is comprised of a CRC Encoder, BB (baseband)Frame Slicer, and BB Frame Header Insertion block.

The CRC Encoder provides three kinds of CRC encoding for error detectionat the user packet (UP) level, i.e., CRC-8, CRC-16, and CRC-32. Thecomputed CRC bytes are appended after the UP. CRC-8 is used for TSstream and CRC-32 for IP stream. If the GS stream doesn't provide theCRC encoding, the proposed CRC encoding should be applied.

BB Frame Slicer maps the input into an internal logical-bit format. Thefirst received bit is defined to be the MSB. The BB Frame Slicerallocates a number of input bits equal to the available data fieldcapacity. To allocate a number of input bits equal to the BBF payload,the UP packet stream is sliced to fit the data field of BBF.

BB Frame Header Insertion block can insert fixed length BBF header of 2bytes is inserted in front of the BB Frame. The BBF header is composedof STUFFI (1 bit), SYNCD (13 bits), and RFU (2 bits). In addition to thefixed 2-Byte BBF header, BBF can have an extension field (1 or 3 bytes)at the end of the 2-byte BBF header.

The stream adaptation 2010 is comprised of stuffing insertion block andBB scrambler.

The stuffing insertion block can insert stuffing field into a payload ofa BB frame. If the input data to the stream adaptation is sufficient tofill a BB-Frame, STUFFI is set to ‘0’ and the BBF has no stuffing field.Otherwise STUFFI is set to ‘1’ and the stuffing field is insertedimmediately after the BBF header. The stuffing field comprises two bytesof the stuffing field header and a variable size of stuffing data.

The BB scrambler scrambles complete BBF for energy dispersal. Thescrambling sequence is synchronous with the BBF. The scrambling sequenceis generated by the feed-back shift register.

The PLS generation block 2020 can generate physical layer signaling(PLS) data. The PLS provides the receiver with a means to accessphysical layer DPs. The PLS data consists of PLS1 data and PLS2 data.

The PLS1 data is a first set of PLS data carried in the FSS symbols inthe frame having a fixed size, coding and modulation, which carriesbasic information about the system as well as the parameters needed todecode the PLS2 data. The PLS1 data provides basic transmissionparameters including parameters required to enable the reception anddecoding of the PLS2 data. Also, the PLS1 data remains constant for theduration of a frame-group.

The PLS2 data is a second set of PLS data transmitted in the FSS symbol,which carries more detailed PLS data about the system and the DPs. ThePLS2 contains parameters that provide sufficient information for thereceiver to decode the desired DP. The PLS2 signaling further consistsof two types of parameters, PLS2 Static data (PLS2-STAT data) and PLS2dynamic data (PLS2-DYN data). The PLS2 Static data is PLS2 data thatremains static for the duration of a frame-group and the PLS2 dynamicdata is PLS2 data that may dynamically change frame-by-frame.

Details of the PLS data will be described later.

The PLS scrambler 2030 can scramble the generated PLS data for energydispersal.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 3 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 3 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 3 shows a mode adaptation block of the input formatting block whenthe input signal corresponds to multiple input streams.

The mode adaptation block of the input formatting block for processingthe multiple input streams can independently process the multiple inputstreams.

Referring to FIG. 3, the mode adaptation block for respectivelyprocessing the multiple input streams can include an input streamsplitter 3000, an input stream synchronizer 3010, a compensating delayblock 3020, a null packet deletion block 3030, a head compression block3040, a CRC encoder 3050, a BB frame slicer 3060 and a BB headerinsertion block 3070. Description will be given of each block of themode adaptation block.

Operations of the CRC encoder 3050, BB frame slicer 3060 and BB headerinsertion block 3070 correspond to those of the CRC encoder, BB frameslicer and BB header insertion block described with reference to FIG. 2and thus description thereof is omitted.

The input stream splitter 3000 can split the input TS, IP, GS streamsinto multiple service or service component (audio, video, etc.) streams.

The input stream synchronizer 3010 may be referred as ISSY. The ISSY canprovide suitable means to guarantee Constant Bit Rate (CBR) and constantend-to-end transmission delay for any input data format. The ISSY isalways used for the case of multiple DPs carrying TS, and optionallyused for multiple DPs carrying GS streams.

The compensating delay block 3020 can delay the split TS packet streamfollowing the insertion of ISSY information to allow a TS packetrecombining mechanism without requiring additional memory in thereceiver.

The null packet deletion block 3030, is used only for the TS inputstream case. Some TS input streams or split TS streams may have a largenumber of null-packets present in order to accommodate VBR (variablebit-rate) services in a CBR TS stream. In this case, in order to avoidunnecessary transmission overhead, null-packets can be identified andnot transmitted. In the receiver, removed null-packets can bere-inserted in the exact place where they were originally by referenceto a deleted null-packet (DNP) counter that is inserted in thetransmission, thus guaranteeing constant bit-rate and avoiding the needfor time-stamp (PCR) updating.

The head compression block 3040 can provide packet header compression toincrease transmission efficiency for TS or IP input streams. Because thereceiver can have a priori information on certain parts of the header,this known information can be deleted in the transmitter.

For Transport Stream, the receiver has a-priori information about thesync-byte configuration (0x47) and the packet length (188 Byte). If theinput TS stream carries content that has only one PID, i.e., for onlyone service component (video, audio, etc.) or service sub-component (SVCbase layer, SVC enhancement layer, MVC base view or MVC dependentviews), TS packet header compression can be applied (optionally) to theTransport Stream. IP packet header compression is used optionally if theinput steam is an IP stream.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 4 illustrates an input formatting block according to anotherembodiment of the present invention.

The input formatting block illustrated in FIG. 4 corresponds to anembodiment of the input formatting block 1000 described with referenceto FIG. 1.

FIG. 4 illustrates a stream adaptation block of the input formattingmodule when the input signal corresponds to multiple input streams.

Referring to FIG. 4, the mode adaptation block for respectivelyprocessing the multiple input streams can include a scheduler 4000, an1-Frame delay block 4010, a stuffing insertion block 4020, an in-bandsignaling 4030, a BB Frame scrambler 4040, a PLS generation block 4050and a PLS scrambler 4060. Description will be given of each block of thestream adaptation block.

Operations of the stuffing insertion block 4020, the BB Frame scrambler4040, the PLS generation block 4050 and the PLS scrambler 4060correspond to those of the stuffing insertion block, BB scrambler, PLSgeneration block and the PLS scrambler described with reference to FIG.2 and thus description thereof is omitted.

The scheduler 4000 can determine the overall cell allocation across theentire frame from the amount of FECBLOCKs of each DP. Including theallocation for PLS, EAC and FIC, the scheduler generate the values ofPLS2-DYN data, which is transmitted as in-band signaling or PLS cell inFSS of the frame. Details of FECBLOCK, EAC and FIC will be describedlater.

The 1-Frame delay block 4010 can delay the input data by onetransmission frame such that scheduling information about the next framecan be transmitted through the current frame for in-band signalinginformation to be inserted into the DPs.

The in-band signaling 4030 can insert un-delayed part of the PLS2 datainto a DP of a frame.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 5 illustrates a BICM block according to an embodiment of thepresent invention.

The BICM block illustrated in FIG. 5 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

As described above, the apparatus for transmitting broadcast signals forfuture broadcast services according to an embodiment of the presentinvention can provide a terrestrial broadcast service, mobile broadcastservice, UHDTV service, etc.

Since QoS (quality of service) depends on characteristics of a serviceprovided by the apparatus for transmitting broadcast signals for futurebroadcast services according to an embodiment of the present invention,data corresponding to respective services needs to be processed throughdifferent schemes. Accordingly, the a BICM block according to anembodiment of the present invention can independently process DPs inputthereto by independently applying SISO, MISO and MIMO schemes to thedata pipes respectively corresponding to data paths. Consequently, theapparatus for transmitting broadcast signals for future broadcastservices according to an embodiment of the present invention can controlQoS for each service or service component transmitted through each DP.

(a) shows the BICM block shared by the base profile and the handheldprofile and (b) shows the BICM block of the advanced profile.

The BICM block shared by the base profile and the handheld profile andthe BICM block of the advanced profile can include plural processingblocks for processing each DP.

A description will be given of each processing block of the BICM blockfor the base profile and the handheld profile and the BICM block for theadvanced profile.

A processing block 5000 of the BICM block for the base profile and thehandheld profile can include a Data FEC encoder 5010, a bit interleaver5020, a constellation mapper 5030, an SSD (Signal Space Diversity)encoding block 5040 and a time interleaver 5050.

The Data FEC encoder 5010 can perform the FEC encoding on the input BBFto generate FECBLOCK procedure using outer coding (BCH), and innercoding (LDPC). The outer coding (BCH) is optional coding method. Detailsof operations of the Data FEC encoder 5010 will be described later.

The bit interleaver 5020 can interleave outputs of the Data FEC encoder5010 to achieve optimized performance with combination of the LDPC codesand modulation scheme while providing an efficiently implementablestructure. Details of operations of the bit interleaver 5020 will bedescribed later.

The constellation mapper 5030 can modulate each cell word from the bitinterleaver 5020 in the base and the handheld profiles, or cell wordfrom the Cell-word demultiplexer 5010-1 in the advanced profile usingeither QPSK, QAM-16, non-uniform QAM (NUQ-64, NUQ-256, NUQ-1024) ornon-uniform constellation (NUC-16, NUC64, NUC-256, NUC-1024) to give apower-normalized constellation point, e_(l). This constellation mappingis applied only for DPs. Observe that QAM-16 and NUQs are square shaped,while NUCs have arbitrary shape. When each constellation is rotated byany multiple of 90 degrees, the rotated constellation exactly overlapswith its original one. This “rotation-sense” symmetric property makesthe capacities and the average powers of the real and imaginarycomponents equal to each other. Both NUQs and NUCs are definedspecifically for each code rate and the particular one used is signaledby the parameter DP_MOD filed in PLS2 data.

The SSD encoding block 5040 can precode cells in two (2D), three (3D),and four (4D) dimensions to increase the reception robustness underdifficult fading conditions.

The time interleaver 5050 can operates at the DP level. The parametersof time interleaving (TI) may be set differently for each DP. Details ofoperations of the time interleaver 5050 will be described later.

A processing block 5000-1 of the BICM block for the advanced profile caninclude the Data FEC encoder, bit interleaver, constellation mapper, andtime interleaver. However, the processing block 5000-1 is distinguishedfrom the processing block 5000 further includes a cell-worddemultiplexer 5010-1 and a MIMO encoding block 5020-1.

Also, the operations of the Data FEC encoder, bit interleaver,constellation mapper, and time interleaver in the processing block5000-1 correspond to those of the Data FEC encoder 5010, bit interleaver5020, constellation mapper 5030, and time interleaver 5050 described andthus description thereof is omitted.

The cell-word demultiplexer 5010-1 is used for the DP of the advancedprofile to divide the single cell-word stream into dual cell-wordstreams for MIMO processing. Details of operations of the cell-worddemultiplexer 5010-1 will be described later.

The MIMO encoding block 5020-1 can processing the output of thecell-word demultiplexer 5010-1 using MIMO encoding scheme. The MIMOencoding scheme was optimized for broadcasting signal transmission. TheMIMO technology is a promising way to get a capacity increase but itdepends on channel characteristics. Especially for broadcasting, thestrong LOS component of the channel or a difference in the receivedsignal power between two antennas caused by different signal propagationcharacteristics makes it difficult to get capacity gain from MIMO. Theproposed MIMO encoding scheme overcomes this problem using arotation-based pre-coding and phase randomization of one of the MIMOoutput signals.

MIMO encoding is intended for a 2×2 MIMO system requiring at least twoantennas at both the transmitter and the receiver. Two MIMO encodingmodes are defined in this proposal; full-rate spatial multiplexing(FR-SM) and full-rate full-diversity spatial multiplexing (FRFD-SM). TheFR-SM encoding provides capacity increase with relatively smallcomplexity increase at the receiver side while the FRFD-SM encodingprovides capacity increase and additional diversity gain with a greatcomplexity increase at the receiver side. The proposed MIMO encodingscheme has no restriction on the antenna polarity configuration.

MIMO processing is required for the advanced profile frame, which meansall DPs in the advanced profile frame are processed by the MIMO encoder.MIMO processing is applied at DP level. Pairs of the ConstellationMapper outputs NUQ (e_(1,i) and e_(2,i)) are fed to the input of theMIMO Encoder. Paired MIMO Encoder output (g1,i and g2,i) is transmittedby the same carrier k and OFDM symbol 1 of their respective TX antennas.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 6 illustrates a BICM block according to another embodiment of thepresent invention.

The BICM block illustrated in FIG. 6 corresponds to an embodiment of theBICM block 1010 described with reference to FIG. 1.

FIG. 6 illustrates a BICM block for protection of physical layersignaling (PLS), emergency alert channel (EAC) and fast informationchannel (FIC). EAC is a part of a frame that carries EAS informationdata and FIC is a logical channel in a frame that carries the mappinginformation between a service and the corresponding base DP. Details ofthe EAC and FIC will be described later.

Referring to FIG. 6, the BICM block for protection of PLS, EAC and FICcan include a PLS FEC encoder 6000, a bit interleaver 6010, aconstellation mapper 6020 and time interleaver 6030.

Also, the PLS FEC encoder 6000 can include a scrambler, BCHencoding/zero insertion block, LDPC encoding block and LDPC paritypuncturing block. Description will be given of each block of the BICMblock.

The PLS FEC encoder 6000 can encode the scrambled PLS1/2 data, EAC andFIC section.

The scrambler can scramble PLS1 data and PLS2 data before BCH encodingand shortened and punctured LDPC encoding.

The BCH encoding/zero insertion block can perform outer encoding on thescrambled PLS1/2 data using the shortened BCH code for PLS protectionand insert zero bits after the BCH encoding. For PLS1 data only, theoutput bits of the zero insertion may be permitted before LDPC encoding.

The LDPC encoding block can encode the output of the BCH encoding/zeroinsertion block using LDPC code. To generate a complete coded block,C_(ldpc), parity bits, P_(ldpc) are encoded systematically from eachzero-inserted PLS information block, I_(ldpc) and appended after it.

MathFigure 1

C _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ , i ₁ , . . . ,i _(K) _(ldpc) ₋₁, p ₀ , p ₁ , . . . , p _(N) _(lpdc) _(-K) _(ldpc) ₋₁]

The LDPC code parameters for PLS1 and PLS2 are as following table 4.

TABLE 4 Signaling K_(ldpc) code Type K_(sig) K_(bch) N_(bch) _(—)_(parity) (=N_(bch)) N_(ldpc) N_(ldpc) _(—) _(parity) rate Q_(ldpc) PLS1342 1020 60 1080 4320 3240 1/4  36 PLS2 <1021 >1020 2100 2160 7200 50403/10 56

The LDPC parity puncturing block can perform puncturing on the PLS1 dataand PLS 2 data.

When shortening is applied to the PLS1 data protection, some LDPC paritybits are punctured after LDPC encoding. Also, for the PLS2 dataprotection, the LDPC parity bits of PLS2 are punctured after LDPCencoding. These punctured bits are not transmitted.

The bit interleaver 6010 can interleave the each shortened and puncturedPLS1 data and PLS2 data.

The constellation mapper 6020 can map the bit interleaved PLS1 data andPLS2 data onto constellations.

The time interleaver 6030 can interleave the mapped PLS1 data and PLS2data.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 7 illustrates a frame building block according to one embodiment ofthe present invention.

The frame building block illustrated in FIG. 7 corresponds to anembodiment of the frame building block 1020 described with reference toFIG. 1.

Referring to FIG. 7, the frame building block can include a delaycompensation block 7000, a cell mapper 7010 and a frequency interleaver7020. Description will be given of each block of the frame buildingblock.

The delay compensation block 7000 can adjust the timing between the datapipes and the corresponding PLS data to ensure that they are co-timed atthe transmitter end. The PLS data is delayed by the same amount as datapipes are by addressing the delays of data pipes caused by the InputFormatting block and BICM block. The delay of the BICM block is mainlydue to the time interleaver. In-band signaling data carries informationof the next TI group so that they are carried one frame ahead of the DPsto be signaled. The Delay Compensating block delays in-band signalingdata accordingly.

The cell mapper 7010 can map PLS, EAC, FIC, DPs, auxiliary streams anddummy cells into the active carriers of the OFDM symbols in the frame.The basic function of the cell mapper 7010 is to map data cells producedby the TIs for each of the DPs, PLS cells, and EAC/FIC cells, if any,into arrays of active OFDM cells corresponding to each of the OFDMsymbols within a frame. Service signaling data (such as PSI (programspecific information)/SI) can be separately gathered and sent by a datapipe. The Cell Mapper operates according to the dynamic informationproduced by the scheduler and the configuration of the frame structure.Details of the frame will be described later.

The frequency interleaver 7020 can randomly interleave data cellsreceived from the cell mapper 7010 to provide frequency diversity. Also,the frequency interleaver 7020 can operate on very OFDM symbol paircomprised of two sequential OFDM symbols using a differentinterleaving-seed order to get maximum interleaving gain in a singleframe. Details of operations of the frequency interleaver 7020 will bedescribed later.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions.

FIG. 8 illustrates an OFMD generation block according to an embodimentof the present invention.

The OFMD generation block illustrated in FIG. 8 corresponds to anembodiment of the OFMD generation block 1030 described with reference toFIG. 1.

The OFDM generation block modulates the OFDM carriers by the cellsproduced by the Frame Building block, inserts the pilots, and producesthe time domain signal for transmission. Also, this block subsequentlyinserts guard intervals, and applies PAPR (Peak-to-Average Power Radio)reduction processing to produce the final RF signal.

Referring to FIG. 8, the frame building block can include a pilot andreserved tone insertion block 8000, a 2D-eSFN encoding block 8010, anIFFT (Inverse Fast Fourier Transform) block 8020, a PAPR reduction block8030, a guard interval insertion block 8040, a preamble insertion block8050, other system insertion block 8060 and a DAC block 8070.Description will be given of each block of the frame building block.

The pilot and reserved tone insertion block 8000 can insert pilots andthe reserved tone.

Various cells within the OFDM symbol are modulated with referenceinformation, known as pilots, which have transmitted values known apriori in the receiver. The information of pilot cells is made up ofscattered pilots, continual pilots, edge pilots, FSS (frame signalingsymbol) pilots and FES (frame edge symbol) pilots. Each pilot istransmitted at a particular boosted power level according to pilot typeand pilot pattern. The value of the pilot information is derived from areference sequence, which is a series of values, one for eachtransmitted carrier on any given symbol. The pilots can be used forframe synchronization, frequency synchronization, time synchronization,channel estimation, and transmission mode identification, and also canbe used to follow the phase noise.

Reference information, taken from the reference sequence, is transmittedin scattered pilot cells in every symbol except the preamble, FSS andFES of the frame. Continual pilots are inserted in every symbol of theframe. The number and location of continual pilots depends on both theFFT size and the scattered pilot pattern. The edge carriers are edgepilots in every symbol except for the preamble symbol. They are insertedin order to allow frequency interpolation up to the edge of thespectrum. FSS pilots are inserted in FSS(s) and FES pilots are insertedin FES. They are inserted in order to allow time interpolation up to theedge of the frame.

The system according to an embodiment of the present invention supportsthe SFN network, where distributed MISO scheme is optionally used tosupport very robust transmission mode. The 2D-eSFN is a distributed MISOscheme that uses multiple TX antennas, each of which is located in thedifferent transmitter site in the SFN network.

The 2D-eSFN encoding block 8010 can process a 2D-eSFN processing todistorts the phase of the signals transmitted from multipletransmitters, in order to create both time and frequency diversity inthe SFN configuration. Hence, burst errors due to low flat fading ordeep-fading for a long time can be mitigated.

The IFFT block 8020 can modulate the output from the 2D-eSFN encodingblock 8010 using OFDM modulation scheme. Any cell in the data symbolswhich has not been designated as a pilot (or as a reserved tone) carriesone of the data cells from the frequency interleaver. The cells aremapped to OFDM carriers.

The PAPR reduction block 8030 can perform a PAPR reduction on inputsignal using various PAPR reduction algorithm in the time domain.

The guard interval insertion block 8040 can insert guard intervals andthe preamble insertion block 8050 can insert preamble in front of thesignal. Details of a structure of the preamble will be described later.The other system insertion block 8060 can multiplex signals of aplurality of broadcast transmission/reception systems in the time domainsuch that data of two or more different broadcast transmission/receptionsystems providing broadcast services can be simultaneously transmittedin the same RF signal bandwidth. In this case, the two or more differentbroadcast transmission/reception systems refer to systems providingdifferent broadcast services. The different broadcast services may referto a terrestrial broadcast service, mobile broadcast service, etc. Datarelated to respective broadcast services can be transmitted throughdifferent frames.

The DAC block 8070 can convert an input digital signal into an analogsignal and output the analog signal. The signal output from the DACblock 7800 can be transmitted through multiple output antennas accordingto the physical layer profiles. A Tx antenna according to an embodimentof the present invention can have vertical or horizontal polarity.

The above-described blocks may be omitted or replaced by blocks havingsimilar or identical functions according to design.

FIG. 9 illustrates a structure of an apparatus for receiving broadcastsignals for future broadcast services according to an embodiment of thepresent invention.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention cancorrespond to the apparatus for transmitting broadcast signals forfuture broadcast services, described with reference to FIG. 1.

The apparatus for receiving broadcast signals for future broadcastservices according to an embodiment of the present invention can includea synchronization & demodulation module 9000, a frame parsing module9010, a demapping & decoding module 9020, an output processor 9030 and asignaling decoding module 9040. A description will be given of operationof each module of the apparatus for receiving broadcast signals.

The synchronization & demodulation module 9000 can receive input signalsthrough m Rx antennas, perform signal detection and synchronization withrespect to a system corresponding to the apparatus for receivingbroadcast signals and carry out demodulation corresponding to a reverseprocedure of the procedure performed by the apparatus for transmittingbroadcast signals.

The frame parsing module 9100 can parse input signal frames and extractdata through which a service selected by a user is transmitted. If theapparatus for transmitting broadcast signals performs interleaving, theframe parsing module 9100 can carry out deinterleaving corresponding toa reverse procedure of interleaving. In this case, the positions of asignal and data that need to be extracted can be obtained by decodingdata output from the signaling decoding module 9400 to restorescheduling information generated by the apparatus for transmittingbroadcast signals.

The demapping & decoding module 9200 can convert the input signals intobit domain data and then deinterleave the same as necessary. Thedemapping & decoding module 9200 can perform demapping for mappingapplied for transmission efficiency and correct an error generated on atransmission channel through decoding. In this case, the demapping &decoding module 9200 can obtain transmission parameters necessary fordemapping and decoding by decoding the data output from the signalingdecoding module 9400.

The output processor 9300 can perform reverse procedures of variouscompression/signal processing procedures which are applied by theapparatus for transmitting broadcast signals to improve transmissionefficiency. In this case, the output processor 9300 can acquirenecessary control information from data output from the signalingdecoding module 9400. The output of the output processor 8300corresponds to a signal input to the apparatus for transmittingbroadcast signals and may be MPEG-TSs, IP streams (v4 or v6) and genericstreams.

The signaling decoding module 9400 can obtain PLS information from thesignal demodulated by the synchronization & demodulation module 9000. Asdescribed above, the frame parsing module 9100, demapping & decodingmodule 9200 and output processor 9300 can execute functions thereofusing the data output from the signaling decoding module 9400.

FIG. 10 illustrates a frame structure according to an embodiment of thepresent invention.

FIG. 10 shows an example configuration of the frame types and FRUs in asuper-frame. (a) shows a super frame according to an embodiment of thepresent invention, (b) shows FRU (Frame Repetition Unit) according to anembodiment of the present invention, (c) shows frames of variable PHYprofiles in the FRU and (d) shows a structure of a frame.

A super-frame may be composed of eight FRUs. The FRU is a basicmultiplexing unit for TDM of the frames, and is repeated eight times ina super-frame.

Each frame in the FRU belongs to one of the PHY profiles, (base,handheld, advanced) or FEF. The maximum allowed number of the frames inthe FRU is four and a given PHY profile can appear any number of timesfrom zero times to four times in the FRU (e.g., base, base, handheld,advanced). PHY profile definitions can be extended using reserved valuesof the PHY_PROFILE in the preamble, if required.

The FEF part is inserted at the end of the FRU, if included. When theFEF is included in the FRU, the minimum number of FEFs is 8 in asuper-frame. It is not recommended that FEF parts be adjacent to eachother.

One frame is further divided into a number of OFDM symbols and apreamble. As shown in (d), the frame comprises a preamble, one or moreframe signaling symbols (FSS), normal data symbols and a frame edgesymbol (FES).

The preamble is a special symbol that enables fast Futurecast UTB systemsignal detection and provides a set of basic transmission parameters forefficient transmission and reception of the signal. The detaileddescription of the preamble will be will be described later.

The main purpose of the FSS(s) is to carry the PLS data. For fastsynchronization and channel estimation, and hence fast decoding of PLSdata, the FSS has more dense pilot pattern than the normal data symbol.The FES has exactly the same pilots as the FSS, which enablesfrequency-only interpolation within the FES and temporal interpolation,without extrapolation, for symbols immediately preceding the FES.

FIG. 11 illustrates a signaling hierarchy structure of the frameaccording to an embodiment of the present invention.

FIG. 11 illustrates the signaling hierarchy structure, which is splitinto three main parts: the preamble signaling data 11000, the PLS1 data11010 and the PLS2 data 11020. The purpose of the preamble, which iscarried by the preamble symbol in every frame, is to indicate thetransmission type and basic transmission parameters of that frame. ThePLS1 enables the receiver to access and decode the PLS2 data, whichcontains the parameters to access the DP of interest. The PLS2 iscarried in every frame and split into two main parts: PLS2-STAT data andPLS2-DYN data. The static and dynamic portion of PLS2 data is followedby padding, if necessary.

FIG. 12 illustrates preamble signaling data according to an embodimentof the present invention.

Preamble signaling data carries 21 bits of information that are neededto enable the receiver to access PLS data and trace DPs within the framestructure. Details of the preamble signaling data are as follows:

PHY_PROFILE: This 3-bit field indicates the PHY profile type of thecurrent frame. The mapping of different PHY profile types is given inbelow table 5.

TABLE 5 Value PHY profile 000 Base profile 001 Handheld profile 010Advanced profiled 011~110 Reserved 111 FEF

FFT_SIZE: This 2 bit field indicates the FFT size of the current framewithin a frame-group, as described in below table 6.

TABLE 6 Value FFT size 00  8K FFT 01 16K FFT 10 32K FFT 11 Reserved

GI_FRACTION: This 3 bit field indicates the guard interval fractionvalue in the current super-frame, as described in below table 7.

TABLE 7 Value GI_FRACTION 000 ⅕ 001 1/10 010 1/20 011 1/40 100 1/80 1011/160 110~111 Reserved

EAC_FLAG: This 1 bit field indicates whether the EAC is provided in thecurrent frame. If this field is set to ‘1’, emergency alert service(EAS) is provided in the current frame. If this field set to ‘0’, EAS isnot carried in the current frame. This field can be switched dynamicallywithin a super-frame.

PILOT_MODE: This 1-bit field indicates whether the pilot mode is mobilemode or fixed mode for the current frame in the current frame-group. Ifthis field is set to ‘0’, mobile pilot mode is used. If the field is setto ‘1’, the fixed pilot mode is used.

PAPR_FLAG: This 1-bit field indicates whether PAPR reduction is used forthe current frame in the current frame-group. If this field is set tovalue ‘1’, tone reservation is used for PAPR reduction. If this field isset to ‘0’, PAPR reduction is not used.

FRU_CONFIGURE: This 3-bit field indicates the PHY profile typeconfigurations of the frame repetition units (FRU) that are present inthe current super-frame. All profile types conveyed in the currentsuper-frame are identified in this field in all preambles in the currentsuper-frame. The 3-bit field has a different definition for eachprofile, as show in below table 8.

TABLE 8 Current Current Current PHY_PROFILE = PHY_PROFILE = CurrentPHY_PROFILE = ‘001’ ‘010’ PHY_PROFILE = ‘000’ (base) (handheld)(advanced) ‘111’ (FEF) FRU_CONFIGURE = Only base Only handheld Onlyadvanced Only FEF 000 profile profile present profile present presentpresent FRU_CONFIGURE = Handheld profile Base profile Base profile Baseprofile 1XX present present present present FRU_CONFIGURE = AdvancedAdvanced Handheld profile Handheld profile X1X profile profile presentpresent present present FRU_CONFIGURE = FEF FEF FEF Advanced XX1 presentpresent present profile present

RESERVED: This 7-bit field is reserved for future use.

FIG. 13 illustrates PLS1 data according to an embodiment of the presentinvention.

PLS1 data provides basic transmission parameters including parametersrequired to enable the reception and decoding of the PLS2. As abovementioned, the PLS1 data remain unchanged for the entire duration of oneframe-group. The detailed definition of the signaling fields of the PLS1data are as follows:

PREAMBLE_DATA: This 20-bit field is a copy of the preamble signalingdata excluding the EAC_FLAG.

NUM_FRAME_FRU: This 2-bit field indicates the number of the frames perFRU.

PAYLOAD_TYPE: This 3-bit field indicates the format of the payload datacarried in the frame-group. PAYLOAD_TYPE is signaled as shown in table9.

TABLE 9 value Payload type 1XX TS stream is transmitted X1X IP stream istransmitted XX1 GS stream is transmitted

NUM_FSS: This 2-bit field indicates the number of FSS symbols in thecurrent frame.

SYSTEM_VERSION: This 8-bit field indicates the version of thetransmitted signal format. The SYSTEM_VERSION is divided into two 4-bitfields, which are a major version and a minor version.

Major version: The MSB four bits of SYSTEM_VERSION field indicate majorversion information. A change in the major version field indicates anon-backward-compatible change. The default value is ‘0000’. For theversion described in this standard, the value is set to ‘0000’.

Minor version: The LSB four bits of SYSTEM_VERSION field indicate minorversion information. A change in the minor version field isbackward-compatible.

CELL_ID: This is a 16-bit field which uniquely identifies a geographiccell in an ATSC network. An ATSC cell coverage area may consist of oneor more frequencies, depending on the number of frequencies used perFuturecast UTB system. If the value of the CELL_ID is not known orunspecified, this field is set to ‘0’.

NETWORK_ID: This is a 16-bit field which uniquely identifies the currentATSC network.

SYSTEM_ID: This 16-bit field uniquely identifies the Futurecast UTBsystem within the ATSC network. The Futurecast UTB system is theterrestrial broadcast system whose input is one or more input streams(TS, IP, GS) and whose output is an RF signal. The Futurecast UTB systemcarries one or more PHY profiles and FEF, if any. The same FuturecastUTB system may carry different input streams and use different RFfrequencies in different geographical areas, allowing local serviceinsertion. The frame structure and scheduling is controlled in one placeand is identical for all transmissions within a Futurecast UTB system.One or more Futurecast UTB systems may have the same SYSTEM_ID meaningthat they all have the same physical layer structure and configuration.

The following loop consists of FRU_PHY_PROFILE, FRU_FRAME_LENGTH,FRU_GI_FRACTION, and RESERVED which are used to indicate the FRUconfiguration and the length of each frame type. The loop size is fixedso that four PHY profiles (including a FEF) are signaled within the FRU.If NUM_FRAME_FRU is less than 4, the unused fields are filled withzeros.

FRU_PHY_PROFILE: This 3-bit field indicates the PHY profile type of the(i+1)th (i is the loop index) frame of the associated FRU. This fielduses the same signaling format as shown in the table 8.

FRU_FRAME_LENGTH: This 2-bit field indicates the length of the (i+1)thframe of the associated FRU. Using FRU_FRAME_LENGTH together withFRU_GI_FRACTION, the exact value of the frame duration can be obtained.

FRU_GI_FRACTION: This 3-bit field indicates the guard interval fractionvalue of the (i+1)th frame of the associated FRU. FRU_GI_FRACTION issignaled according to the table 7.

RESERVED: This 4-bit field is reserved for future use.

The following fields provide parameters for decoding the PLS2 data.

PLS2_FEC_TYPE: This 2-bit field indicates the FEC type used by the PLS2protection. The FEC type is signaled according to table 10. The detailsof the LDPC codes will be described later.

TABLE 10 Content PLS2 FEC type 00 4K-1/4 and 7K-3/10 LDPC codes 01~11Reserved

PLS2_MOD: This 3-bit field indicates the modulation type used by thePLS2. The modulation type is signaled according to table 11.

TABLE 11 Value PLS2_MODE 000 BPSK 001 QPSK 010 QAM-16 011 NUQ-64 100~111Reserved

PLS2_SIZE_CELL: This 15-bit field indicates C_(total) _(_) _(partial)_(_) _(block), the size (specified as the number of QAM cells) of thecollection of full coded blocks for PLS2 that is carried in the currentframe-group. This value is constant during the entire duration of thecurrent frame-group.

PLS2_STAT_SIZE_BIT: This 14-bit field indicates the size, in bits, ofthe PLS2-STAT for the current frame-group. This value is constant duringthe entire duration of the current frame-group.

PLS2_DYN_SIZE_BIT: This 14-bit field indicates the size, in bits, of thePLS2-DYN for the current frame-group. This value is constant during theentire duration of the current frame-group.

PLS2_REP_FLAG: This 1-bit flag indicates whether the PLS2 repetitionmode is used in the current frame-group. When this field is set to value‘1’, the PLS2 repetition mode is activated. When this field is set tovalue ‘0’, the PLS2 repetition mode is deactivated.

PLS2_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(partial) _(_) _(block), the size (specified as the number of QAMcells) of the collection of partial coded blocks for PLS2 carried inevery frame of the current frame-group, when PLS2 repetition is used. Ifrepetition is not used, the value of this field is equal to 0. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_FEC_TYPE: This 2-bit field indicates the FEC type used forPLS2 that is carried in every frame of the next frame-group. The FECtype is signaled according to the table 10.

PLS2_NEXT_MOD: This 3-bit field indicates the modulation type used forPLS2 that is carried in every frame of the next frame-group. Themodulation type is signaled according to the table 11.

PLS2_NEXT_REP_FLAG: This 1-bit flag indicates whether the PLS2repetition mode is used in the next frame-group. When this field is setto value ‘1’, the PLS2 repetition mode is activated. When this field isset to value ‘0’, the PLS2 repetition mode is deactivated.

PLS2_NEXT_REP_SIZE_CELL: This 15-bit field indicates C_(total) _(_)_(partial) _(_) _(block), The size (specified as the number of QAMcells) of the collection of full coded blocks for PLS2 that is carriedin every frame of the next frame-group, when PLS2 repetition is used. Ifrepetition is not used in the next frame-group, the value of this fieldis equal to 0. This value is constant during the entire duration of thecurrent frame-group.

PLS2_NEXT_REP_STAT_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-STAT for the next frame-group. This value is constantin the current frame-group.

PLS2_NEXT_REP DYN_SIZE_BIT: This 14-bit field indicates the size, inbits, of the PLS2-DYN for the next frame-group. This value is constantin the current frame-group.

PLS2_AP_MODE: This 2-bit field indicates whether additional parity isprovided for PLS2 in the current frame-group. This value is constantduring the entire duration of the current frame-group. The below table12 gives the values of this field. When this field is set to ‘00’,additional parity is not used for the PLS2 in the current frame-group.

TABLE 12 Value PLS2-AP mode 00 AP is not provided 01 AP1 mode 10~11Reserved

PLS2_AP_SIZE_CELL: This 15-bit field indicates the size (specified asthe number of QAM cells) of the additional parity bits of the PLS2. Thisvalue is constant during the entire duration of the current frame-group.

PLS2_NEXT_AP_MODE: This 2-bit field indicates whether additional parityis provided for PLS2 signaling in every frame of next frame-group. Thisvalue is constant during the entire duration of the current frame-group.The table 12 defines the values of this field

PLS2_NEXT_AP_SIZE_CELL: This 15-bit field indicates the size (specifiedas the number of QAM cells) of the additional parity bits of the PLS2 inevery frame of the next frame-group. This value is constant during theentire duration of the current frame-group.

RESERVED: This 32-bit field is reserved for future use.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS1 signaling.

FIG. 14 illustrates PLS2 data according to an embodiment of the presentinvention.

FIG. 14 illustrates PLS2-STAT data of the PLS2 data. The PLS2-STAT dataare the same within a frame-group, while the PLS2-DYN data provideinformation that is specific for the current frame.

The details of fields of the PLS2-STAT data are as follows:

FIC_FLAG: This 1-bit field indicates whether the FIC is used in thecurrent frame-group. If this field is set to ‘1’, the FIC is provided inthe current frame. If this field set to ‘0’, the FIC is not carried inthe current frame. This value is constant during the entire duration ofthe current frame-group.

AUX_FLAG: This 1-bit field indicates whether the auxiliary stream(s) isused in the current frame-group. If this field is set to ‘1’, theauxiliary stream is provided in the current frame. If this field set to‘0’, the auxiliary stream is not carried in the current frame. Thisvalue is constant during the entire duration of current frame-group.

NUM_DP: This 6-bit field indicates the number of DPs carried within thecurrent frame. The value of this field ranges from 1 to 64, and thenumber of DPs is NUM_DP+1.

DP_ID: This 6-bit field identifies uniquely a DP within a PHY profile.

DP_TYPE: This 3-bit field indicates the type of the DP. This is signaledaccording to the below table 13.

TABLE 13 Value DP Type 000 DP Type 1 001 DP Type 2 010~111 reserved

DP_GROUP_ID: This 8-bit field identifies the DP group with which thecurrent DP is associated. This can be used by a receiver to access theDPs of the service components associated with a particular service,which will have the same DP_GROUP_ID.

BASE_DP_ID: This 6-bit field indicates the DP carrying service signalingdata (such as PSI/SI) used in the Management layer. The DP indicated byBASE_DP_ID may be either a normal DP carrying the service signaling dataalong with the service data or a dedicated DP carrying only the servicesignaling data

DP_FEC_TYPE: This 2-bit field indicates the FEC type used by theassociated DP. The FEC type is signaled according to the below table 14.

TABLE 14 Value FEC_TYPE 00 16K LDPC 01 64K LDPC 10~11 Reserved

DP_COD: This 4-bit field indicates the code rate used by the associatedDP. The code rate is signaled according to the below table 15.

TABLE 15 Value Code rate 0000 5/15 0001 6/15 0010 7/15 0011 8/15 01009/15 0101 10/15  0110 11/15  0111 12/15  1000 13/15  1001~1111 Reserved

DP_MOD: This 4-bit field indicates the modulation used by the associatedDP. The modulation is signaled according to the below table 16.

TABLE 16 Value Modulation 0000 QPSK 0001 QAM-16 0010 NUQ-64 0011 NUQ-2560100 NUQ-1024 0101 NUC-16 0110 NUC-64 0111 NUC-256 1000 NUC-10241001~1111 reserved

DP_SSD_FLAG: This 1-bit field indicates whether the SSD mode is used inthe associated DP. If this field is set to value ‘1’, SSD is used. Ifthis field is set to value ‘0’, SSD is not used.

The following field appears only if PHY_PROFILE is equal to ‘010’, whichindicates the advanced profile:

DP_MIMO: This 3-bit field indicates which type of MIMO encoding processis applied to the associated DP. The type of MIMO encoding process issignaled according to the table 17.

TABLE 17 Value MIMO encoding 000 FR-SM 001 FRFD-SM 010~111 reserved

DP_TI_TYPE: This 1-bit field indicates the type of time-interleaving. Avalue of ‘0’ indicates that one TI group corresponds to one frame andcontains one or more TI-blocks. A value of ‘1’ indicates that one TIgroup is carried in more than one frame and contains only one TI-block.

DP_TI_LENGTH: The use of this 2-bit field (the allowed values are only1, 2, 4, 8) is determined by the values set within the DP_TI_TYPE fieldas follows:

If the DP_TI_TYPE is set to the value ‘1’, this field indicates P_(I),the number of the frames to which each TI group is mapped, and there isone TI-block per TI group (N_(TI)=1). The allowed P_(I) values with2-bit field are defined in the below table 18.

If the DP_TI_TYPE is set to the value ‘0’, this field indicates thenumber of TI-blocks N_(TI) per TI group, and there is one TI group perframe (P_(I)=1). The allowed P_(I) values with 2-bit field are definedin the below table 18.

TABLE 18 2-bit field P_(I) N_(TI) 00 1 1 01 2 2 10 4 3 11 8 4

DP_FRAME_INTERVAL: This 2-bit field indicates the frame interval(I_(JUMP)) within the frame-group for the associated DP and the allowedvalues are 1, 2, 4, 8 (the corresponding 2-bit field is ‘00’, ‘01’,‘10’, or ‘11’, respectively). For DPs that do not appear every frame ofthe frame-group, the value of this field is equal to the intervalbetween successive frames. For example, if a DP appears on the frames 1,5, 9, 13, etc., this field is set to ‘4’. For DPs that appear in everyframe, this field is set to ‘1’.

DP_TI_BYPASS: This 1-bit field determines the availability of timeinterleaver. If time interleaving is not used for a DP, it is set to‘1’. Whereas if time interleaving is used it is set to ‘0’.

DP_FIRST_FRAME_IDX: This 5-bit field indicates the index of the firstframe of the super-frame in which the current DP occurs. The value ofDP_FIRST_FRAME_IDX ranges from 0 to 31

DP_NUM_BLOCK_MAX: This 10-bit field indicates the maximum value of

DP_NUM_BLOCKS for this DP. The value of this field has the same range asDP_NUM_BLOCKS.

DP_PAYLOAD_TYPE: This 2-bit field indicates the type of the payload datacarried by the given DP. DP_PAYLOAD_TYPE is signaled according to thebelow table 19.

TABLE 19 Value Payload Type 00 TS 01 IP 10 GS 11 reserved

DP_INBAND_MODE: This 2-bit field indicates whether the current DPcarries in-band signaling information. The in-band signaling type issignaled according to the below table 20.

TABLE 20 Value In-band mode 00 In-band signaling is not carried. 01INBAND-PLS is carried only 10 INBAND-ISSY is carried only 11 INBAND-PLSand INBAND-ISSY are carried

DP_PROTOCOL_TYPE: This 2-bit field indicates the protocol type of thepayload carried by the given DP. It is signaled according to the belowtable 21 when input payload types are selected.

TABLE 21 If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE If DP_PAYLOAD_TYPE ValueIs TS Is IP Is GS 00 MPEG2-TS IPv4 (Note) 01 Reserved IPv6 Reserved 10Reserved Reserved Reserved 11 Reserved Reserved Reserved

DP_CRC_MODE: This 2-bit field indicates whether CRC encoding is used inthe Input Formatting block. The CRC mode is signaled according to thebelow table 22.

TABLE 22 Value CRC mode 00 Not used 01 CRC-8 10 CRC-16 11 CRC-32

DNP_MODE: This 2-bit field indicates the null-packet deletion mode usedby the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). DNP_MODEis signaled according to the below table 23. If DP_PAYLOAD_TYPE is notTS (‘00’), DNP_MODE is set to the value ‘00’.

TABLE 23 Value Null-packet deletion mode 00 Not used 01 DNP-NORMAL 10DNP-OFFSET 11 reserved

ISSY_MODE: This 2-bit field indicates the ISSY mode used by theassociated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). The ISSY_MODE issignaled according to the below table 24 If DP_PAYLOAD_TYPE is not TS(‘00’), ISSY_MODE is set to the value ‘00’.

TABLE 24 Value ISSY mode 00 Not used 01 ISSY-UP 10 ISSY-BBF 11 reserved

HC_MODE_TS: This 2-bit field indicates the TS header compression modeused by the associated DP when DP_PAYLOAD_TYPE is set to TS (‘00’). TheHC_MODE_TS is signaled according to the below table 25.

TABLE 25 Value Header compression mode 00 HC_MODE_TS 1 01 HC_MODE_TS 210 HC_MODE_TS 3 11 HC_MODE_TS 4

HC_MODE_IP: This 2-bit field indicates the IP header compression modewhen DP_PAYLOAD_TYPE is set to IP (‘01’). The HC_MODE_IP is signaledaccording to the below table 26.

TABLE 26 Value Header compression mode 00 No compression 01 HC_MODE_IP 110~11 reserved

PID: This 13-bit field indicates the PID number for TS headercompression when DP_PAYLOAD_TYPE is set to TS (‘00’) and HC_MODE_TS isset to ‘01’ or ‘10’.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if FIC_FLAG is equal to ‘1’:

FIC_VERSION: This 8-bit field indicates the version number of the FIC.

FIC_LENGTH_BYTE: This 13-bit field indicates the length, in bytes, ofthe FIC.

RESERVED: This 8-bit field is reserved for future use.

The following field appears only if AUX_FLAG is equal to ‘1’:

NUM_AUX: This 4-bit field indicates the number of auxiliary streams.Zero means no auxiliary streams are used.

AUX_CONFIG_RFU: This 8-bit field is reserved for future use.

AUX_STREAM_TYPE: This 4-bit is reserved for future use for indicatingthe type of the current auxiliary stream.

AUX_PRIVATE_CONFIG: This 28-bit field is reserved for future use forsignaling auxiliary streams.

FIG. 15 illustrates PLS2 data according to another embodiment of thepresent invention.

FIG. 15 illustrates PLS2-DYN data of the PLS2 data. The values of thePLS2-DYN data may change during the duration of one frame-group, whilethe size of fields remains constant.

The details of fields of the PLS2-DYN data are as follows:

FRAME_INDEX: This 5-bit field indicates the frame index of the currentframe within the super-frame. The index of the first frame of thesuper-frame is set to ‘0’.

PLS_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration will change. The nextsuper-frame with changes in the configuration is indicated by the valuesignaled within this field. If this field is set to the value ‘0000’, itmeans that no scheduled change is foreseen: e.g., value ‘1’ indicatesthat there is a change in the next super-frame.

FIC_CHANGE_COUNTER: This 4-bit field indicates the number ofsuper-frames ahead where the configuration (i.e., the contents of theFIC) will change. The next super-frame with changes in the configurationis indicated by the value signaled within this field. If this field isset to the value ‘0000’, it means that no scheduled change is foreseen:e.g. value ‘0001’ indicates that there is a change in the nextsuper-frame.

RESERVED: This 16-bit field is reserved for future use.

The following fields appear in the loop over NUM_DP, which describe theparameters associated with the DP carried in the current frame.

DP_ID: This 6-bit field indicates uniquely the DP within a PHY profile.

DP_START: This 15-bit (or 13-bit) field indicates the start position ofthe first of the DPs using the DPU addressing scheme. The DP_START fieldhas differing length according to the PHY profile and FFT size as shownin the below table 27.

TABLE 27 DP_START field size PHY profile 64K 16K Base 13 bit 15 bitHandheld — 13 bit Advanced 13 bit 15 bit

DP_NUM_BLOCK: This 10-bit field indicates the number of FEC blocks inthe current TI group for the current DP. The value of DP_NUM_BLOCKranges from 0 to 1023

RESERVED: This 8-bit field is reserved for future use.

The following fields indicate the FIC parameters associated with theEAC.

EAC_FLAG: This 1-bit field indicates the existence of the EAC in thecurrent frame. This bit is the same value as the EAC_FLAG in thepreamble.

EAS_WAKE_UP_VERSION_NUM: This 8-bit field indicates the version numberof a wake-up indication.

If the EAC_FLAG field is equal to ‘1’, the following 12 bits areallocated for EAC_LENGTH_BYTE field. If the EAC_FLAG field is equal to‘0’, the following 12 bits are allocated for EAC_COUNTER.

EAC_LENGTH_BYTE: This 12-bit field indicates the length, in byte, of theEAC.

EAC_COUNTER: This 12-bit field indicates the number of the frames beforethe frame where the EAC arrives.

The following field appears only if the AUX_FLAG field is equal to ‘1’:

AUX_PRIVATE_DYN: This 48-bit field is reserved for future use forsignaling auxiliary streams. The meaning of this field depends on thevalue of AUX_STREAM_TYPE in the configurable PLS2-STAT.

CRC_32: A 32-bit error detection code, which is applied to the entirePLS2.

FIG. 16 illustrates a logical structure of a frame according to anembodiment of the present invention.

As above mentioned, the PLS, EAC, FIC, DPs, auxiliary streams and dummycells are mapped into the active carriers of the OFDM symbols in theframe. The PLS1 and PLS2 are first mapped into one or more FSS(s). Afterthat, EAC cells, if any, are mapped immediately following the PLS field,followed next by FIC cells, if any. The DPs are mapped next after thePLS or EAC, FIC, if any. Type 1 DPs follows first, and Type 2 DPs next.The details of a type of the DP will be described later. In some case,DPs may carry some special data for EAS or service signaling data. Theauxiliary stream or streams, if any, follow the DPs, which in turn arefollowed by dummy cells. Mapping them all together in the abovementioned order, i.e. PLS, EAC, FIC, DPs, auxiliary streams and dummydata cells exactly fill the cell capacity in the frame.

FIG. 17 illustrates PLS mapping according to an embodiment of thepresent invention.

PLS cells are mapped to the active carriers of FSS(s). Depending on thenumber of cells occupied by PLS, one or more symbols are designated asFSS(s), and the number of FSS(s) N_(FSS) is signaled by NUM_FSS in PLS1.The FSS is a special symbol for carrying PLS cells. Since robustness andlatency are critical issues in the PLS, the FSS(s) has higher density ofpilots allowing fast synchronization and frequency-only interpolationwithin the FSS.

PLS cells are mapped to active carriers of the N_(FSS) FSS(s) in atop-down manner as shown in an example in FIG. 17. The PLS1 cells aremapped first from the first cell of the first FSS in an increasing orderof the cell index. The PLS2 cells follow immediately after the last cellof the PLS1 and mapping continues downward until the last cell index ofthe first FSS. If the total number of required PLS cells exceeds thenumber of active carriers of one FSS, mapping proceeds to the next FSSand continues in exactly the same manner as the first FSS.

After PLS mapping is completed, DPs are carried next. If EAC, FIC orboth are present in the current frame, they are placed between PLS and“normal” DPs.

FIG. 18 illustrates EAC mapping according to an embodiment of thepresent invention.

EAC is a dedicated channel for carrying EAS messages and links to theDPs for EAS. EAS support is provided but EAC itself may or may not bepresent in every frame. EAC, if any, is mapped immediately after thePLS2 cells. EAC is not preceded by any of the FIC, DPs, auxiliarystreams or dummy cells other than the PLS cells. The procedure ofmapping the EAC cells is exactly the same as that of the PLS.

The EAC cells are mapped from the next cell of the PLS2 in increasingorder of the cell index as shown in the example in FIG. 18. Depending onthe EAS message size, EAC cells may occupy a few symbols, as shown inFIG. 18.

EAC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required EAC cells exceeds the number of remainingactive carriers of the last FSS mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol, which has more activecarriers than a FSS.

After EAC mapping is completed, the FIC is carried next, if any exists.If FIC is not transmitted (as signaled in the PLS2 field), DPs followimmediately after the last cell of the EAC.

FIG. 19 illustrates FIC mapping according to an embodiment of thepresent invention.

(a) shows an example mapping of FIC cell without EAC and (b) shows anexample mapping of FIC cell with EAC.

FIC is a dedicated channel for carrying cross-layer information toenable fast service acquisition and channel scanning. This informationprimarily includes channel binding information between DPs and theservices of each broadcaster. For fast scan, a receiver can decode FICand obtain information such as broadcaster ID, number of services, andBASE_DP_ID. For fast service acquisition, in addition to FIC, base DPcan be decoded using BASE_DP_ID. Other than the content it carries, abase DP is encoded and mapped to a frame in exactly the same way as anormal DP. Therefore, no additional description is required for a baseDP. The FIC data is generated and consumed in the Management Layer. Thecontent of FIC data is as described in the Management Layerspecification.

The FIC data is optional and the use of FIC is signaled by the FIC_FLAGparameter in the static part of the PLS2. If FIC is used, FIC_FLAG isset to ‘1’ and the signaling field for FIC is defined in the static partof PLS2. Signaled in this field are FIC_VERSION, and FIC_LENGTH_BYTE.FIC uses the same modulation, coding and time interleaving parameters asPLS2. FIC shares the same signaling parameters such as PLS2_MOD andPLS2_FEC. FIC data, if any, is mapped immediately after PLS2 or EAC ifany. FIC is not preceded by any normal DPs, auxiliary streams or dummycells. The method of mapping FIC cells is exactly the same as that ofEAC which is again the same as PLS.

Without EAC after PLS, FIC cells are mapped from the next cell of thePLS2 in an increasing order of the cell index as shown in an example in(a). Depending on the FIC data size, FIC cells may be mapped over a fewsymbols, as shown in (b).

FIC cells follow immediately after the last cell of the PLS2, andmapping continues downward until the last cell index of the last FSS. Ifthe total number of required FIC cells exceeds the number of remainingactive carriers of the last FSS, mapping proceeds to the next symbol andcontinues in exactly the same manner as FSS(s). The next symbol formapping in this case is the normal data symbol which has more activecarriers than a FSS.

If EAS messages are transmitted in the current frame, EAC precedes FIC,and FIC cells are mapped from the next cell of the EAC in an increasingorder of the cell index as shown in (b).

After FIC mapping is completed, one or more DPs are mapped, followed byauxiliary streams, if any, and dummy cells.

FIG. 20 illustrates a type of DP according to an embodiment of thepresent invention.

(a) shows type 1 DP and (b) shows type 2 DP.

After the preceding channels, i.e., PLS, EAC and FIC, are mapped, cellsof the DPs are mapped. A DP is categorized into one of two typesaccording to mapping method:

Type 1 DP: DP is mapped by TDM

Type 2 DP: DP is mapped by FDM

The type of DP is indicated by DP_TYPE field in the static part of PLS2.FIG. 20 illustrates the mapping orders of Type 1 DPs and Type 2 DPs.Type 1 DPs are first mapped in the increasing order of cell index, andthen after reaching the last cell index, the symbol index is increasedby one. Within the next symbol, the DP continues to be mapped in theincreasing order of cell index starting from p=0. With a number of DPsmapped together in one frame, each of the Type 1 DPs are grouped intime, similar to TDM multiplexing of DPs.

Type 2 DPs are first mapped in the increasing order of symbol index, andthen after reaching the last OFDM symbol of the frame, the cell indexincreases by one and the symbol index rolls back to the first availablesymbol and then increases from that symbol index. After mapping a numberof DPs together in one frame, each of the Type 2 DPs are grouped infrequency together, similar to FDM multiplexing of DPs.

Type 1 DPs and Type 2 DPs can coexist in a frame if needed with onerestriction; Type 1 DPs always precede Type 2 DPs. The total number ofOFDM cells carrying Type 1 and Type 2 DPs cannot exceed the total numberof OFDM cells available for transmission of DPs:

MathFigure 2

D _(DP1) +D _(DP2) ≦D _(DP)  [Math. 2]

where DDP1 is the number of OFDM cells occupied by Type 1 DPs, DDP2 isthe number of cells occupied by Type 2 DPs. Since PLS, EAC, FIC are allmapped in the same way as Type 1 DP, they all follow “Type 1 mappingrule”. Hence, overall, Type 1 mapping always precedes Type 2 mapping.

FIG. 21 illustrates DP mapping according to an embodiment of the presentinvention.

(a) shows an addressing of OFDM cells for mapping type 1 DPs and (b)shows an an addressing of OFDM cells for mapping for type 2 DPs.

Addressing of OFDM cells for mapping Type 1 DPs (0, . . . , DDP11) isdefined for the active data cells of Type 1 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 1DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Without EAC and FIC, address 0 refers to the cell immediately followingthe last cell carrying PLS in the last FSS. If EAC is transmitted andFIC is not in the corresponding frame, address 0 refers to the cellimmediately following the last cell carrying EAC. If FIC is transmittedin the corresponding frame, address 0 refers to the cell immediatelyfollowing the last cell carrying FIC. Address 0 for Type 1 DPs can becalculated considering two different cases as shown in (a). In theexample in (a), PLS, EAC and FIC are assumed to be all transmitted.Extension to the cases where either or both of EAC and FIC are omittedis straightforward. If there are remaining cells in the FSS aftermapping all the cells up to FIC as shown on the left side of (a).

Addressing of OFDM cells for mapping Type 2 DPs (0, . . . , DDP21) isdefined for the active data cells of Type 2 DPs. The addressing schemedefines the order in which the cells from the TIs for each of the Type 2DPs are allocated to the active data cells. It is also used to signalthe locations of the DPs in the dynamic part of the PLS2.

Three slightly different cases are possible as shown in (b). For thefirst case shown on the left side of (b), cells in the last FSS areavailable for Type 2 DP mapping. For the second case shown in themiddle, FIC occupies cells of a normal symbol, but the number of FICcells on that symbol is not larger than C_(FSS). The third case, shownon the right side in (b), is the same as the second case except that thenumber of FIC cells mapped on that symbol exceeds C_(FSS)

The extension to the case where Type 1 DP(s) precede Type 2 DP(s) isstraightforward since PLS, EAC and FIC follow the same “Type 1 mappingrule” as the Type 1 DP(s).

A data pipe unit (DPU) is a basic unit for allocating data cells to a DPin a frame.

A DPU is defined as a signaling unit for locating DPs in a frame. A CellMapper 7010 may map the cells produced by the TIs for each of the DPs. ATime interleaver 5050 outputs a series of TI-blocks and each TI-blockcomprises a variable number of XFECBLOCKs which is in turn composed of aset of cells. The number of cells in an XFECBLOCK, N_(cells), isdependent on the FECBLOCK size, N_(ldpc), and the number of transmittedbits per constellation symbol. A DPU is defined as the greatest commondivisor of all possible values of the number of cells in a XFECBLOCK,N_(cells), supported in a given PHY profile. The length of a DPU incells is defined as L_(DPU). Since each PHY profile supports differentcombinations of FECBLOCK size and a different number of bits perconstellation symbol, L_(DPU) is defined on a PHY profile basis.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention.

FIG. 22 illustrates an FEC structure according to an embodiment of thepresent invention before bit interleaving. As above mentioned, Data FECencoder may perform the FEC encoding on the input BBF to generateFECBLOCK procedure using outer coding (BCH), and inner coding (LDPC).The illustrated FEC structure corresponds to the FECBLOCK. Also, theFECBLOCK and the FEC structure have same value corresponding to a lengthof LDPC codeword.

The BCH encoding is applied to each BBF (K_(bch) bits), and then LDPCencoding is applied to BCH-encoded BBF (K_(ldpc) bits=N_(bch) bits) asillustrated in FIG. 22.

The value of N_(ldpc) is either 64800 bits (long FECBLOCK) or 16200 bits(short FECBLOCK).

The below table 28 and table 29 show FEC encoding parameters for a longFECBLOCK and a short FECBLOCK, respectively.

TABLE 28 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 64800 21600 21408 12 192 6/15 2592025728 7/15 30240 30048 8/15 34560 34368 9/15 38880 38688 10/15  4320043008 11/15  47520 47328 12/15  51840 51648 13/15  56160 55968

TABLE 29 BCH error LDPC correction Rate N_(ldpc) K_(ldpc) K_(bch)capability N_(bch) − K_(bch) 5/15 16200 5400 5232 12 168 6/15 6480 63127/15 7560 7392 8/15 8640 8472 9/15 9720 9552 10/15  10800 10632 11/15 11880 11712 12/15  12960 12792 13/15  14040 13872

The details of operations of the BCH encoding and LDPC encoding are asfollows:

A 12-error correcting BCH code is used for outer encoding of the BBF.The BCH generator polynomial for short FECBLOCK and long FECBLOCK areobtained by multiplying together all polynomials.

LDPC code is used to encode the output of the outer BCH encoding. Togenerate a completed B_(ldpc) (FECBLOCK), P_(ldpc) (parity bits) isencoded systematically from each I_(ldpc) (BCH-encoded BBF), andappended to I_(ldpc). The completed B_(ldpc) (FECBLOCK) are expressed asfollow Math figure.

MathFigure 3

B _(ldpc) =[I _(ldpc) P _(ldpc) ]=[i ₀ , i ₁ , . . . , i _(K) _(ldpc) ₋₁, p ₀ , p ₁ , . . . , p _(N) _(ldpc) _(-K) _(ldpc) ₋₁]  [Math. 3]

The parameters for long FECBLOCK and short FECBLOCK are given in theabove table 28 and 29, respectively.

The detailed procedure to calculate N_(ldpc)−K_(ldpc) parity bits forlong FECBLOCK, is as follows:

1) Initialize the parity bits,

MathFigure 4

p ₀ =p ₁ =p ₂ ==P _(N) _(ldpc) _(-K) _(ldpc) ₋₁=0  [Math. 4]

2) Accumulate the first information bit—i₀, at parity bit addressesspecified in the first row of an addresses of parity check matrix. Thedetails of addresses of parity check matrix will be described later. Forexample, for rate 13/15:

MathFigure 5

p ₉₈₃ =p ₉₈₃ ⊕i ₀ p ₂₈₁₅ =p ₂₈₁₅ ⊕i ₀

p ₄₈₃₇ =p ₄₈₃₇ ⊕i ₀ p ₄₉₈₉ =p ₄₉₈₉ ⊕i ₀

p ₆₁₃₈ =p ₆₁₃₈ ⊕i ₀ p ₆₄₅₈ =p ₆₄₅₈ ⊕i ₀

p ₆₉₂₁ =p ₆₉₂₁ ⊕i ₀ p ₆₉₇₄ =p ₆₉₇₄ ⊕i ₀

p ₇₅₇₂ =p ₇₅₇₂ ⊕i ₀ p ₈₂₆₀ =p ₈₂₆₀ ⊕i ₀

p ₈₄₉₆ =p ₈₄₀₆ ⊕i ₀  [Math. 5]

3) For the next 359 information bits, i_(s), s=1, 2, . . . , 359accumulate i₅ at parity bit addresses using following Math figure.

MathFigure 6

{x+(s mod 360)×Q _(ldpc)} mod(N _(ldpc) −K _(ldpc))  [Math. 6]

where x denotes the address of the parity bit accumulator correspondingto the first bit i₀, and Q_(ldpc) is a code rate dependent constantspecified in the addresses of parity check matrix. Continuing with theexample, Q_(ldpc)=24 for rate 13/15, so for information bit i₁, thefollowing operations are performed:

MathFigure 7

p ₁₀₀₇ =p ₁₀₀₇ ⊕i ₁ p ₂₈₁₉ =p ₂₈₃₉ ⊕i ₁

p ₄₈₆₁ =p ₄₈₆₁ ⊕i ₁ p ₅₀₁₃ =p ₅₀₁₃ ⊕i ₁

p ₆₁₆₂ =p ₆₁₆₂ ⊕i ₁ p ₆₄₈₂ =p ₆₄₈₂ ⊕i ₁

p ₆₉₄₅ =p ₆₉₄₅ ⊕i ₁ p ₆₉₉₈ =p ₆₉₉₈ ⊕i ₁

p ₇₅₉₆ =p ₇₅₉₆ ⊕i ₁ p ₈₂₈₄ =p ₈₂₈₄ ⊕i ₁

p ₈₅₂₀ =p ₈₅₂₀ ⊕i ₁  [Math. 7]

4) For the 361st information bit i₃₆₀, the addresses of the parity bitaccumulators are given in the second row of the addresses of paritycheck matrix. In a similar manner the addresses of the parity bitaccumulators for the following 359 information bits i_(s), s=361, 362, .. . , 719 are obtained using the Math FIG. 6, where x denotes theaddress of the parity bit accumulator corresponding to the informationbit i₃₆₀, i.e., the entries in the second row of the addresses of paritycheck matrix.

5) In a similar manner, for every group of 360 new information bits, anew row from addresses of parity check matrixes used to find theaddresses of the parity bit accumulators.

After all of the information bits are exhausted, the final parity bitsare obtained as follows:

6) Sequentially perform the following operations starting with i=1

MathFigure 8

p _(i) =p _(i) ⊕p _(i-1) , i=1, 2, . . . , N _(ldpc) −K_(ldpc)−1  [Math. 8]

where final content of p_(i), i=0, 1, . . . , N_(ldpc)−K_(ldpc)−1 isequal to the parity bit p_(i).

TABLE 30 Code Rate Q_(ldpc) 5/15 120 6/15 108 7/15 96 8/15 84 9/15 7210/15  60 11/15  48 12/15  36 13/15  24

This LDPC encoding procedure for a short FECBLOCK is in accordance witht LDPC encoding procedure for the long FECBLOCK, except replacing thetable 30 with table 31, and replacing the addresses of parity checkmatrix for the long FECBLOCK with the addresses of parity check matrixfor the short FECBLOCK.

TABLE 31 Code Rate Q_(ldpc) 5/15 30 6/15 27 7/15 24 8/15 21 9/15 1810/15  15 11/15  12 12/15  9 13/15  6

FIG. 23 illustrates a bit interleaving according to an embodiment of thepresent invention.

The outputs of the LDPC encoder are bit-interleaved, which consists ofparity interleaving followed by Quasi-Cyclic Block (QCB) interleavingand inner-group interleaving.

(a) shows Quasi-Cyclic Block (QCB) interleaving and (b) showsinner-group interleaving.

The FECBLOCK may be parity interleaved. At the output of the parityinterleaving, the LDPC codeword consists of 180 adjacent QC blocks in along FECBLOCK and 45 adjacent QC blocks in a short FECBLOCK. Each QCblock in either a long or short FECBLOCK consists of 360 bits. Theparity interleaved LDPC codeword is interleaved by QCB interleaving. Theunit of QCB interleaving is a QC block. The QC blocks at the output ofparity interleaving are permutated by QCB interleaving as illustrated inFIG. 23, where N_(cells)=64800/η_(mod) or 16200/η_(mod) according to theFECBLOCK length. The QCB interleaving pattern is unique to eachcombination of modulation type and LDPC code rate.

After QCB interleaving, inner-group interleaving is performed accordingto modulation type and order (η_(mod)) which is defined in the belowtable 32. The number of QC blocks for one inner-group, N Q_(QCB) _(_)_(IG), is also defined.

TABLE 32 Modulation type η_(mod) N_(QCB) _(—) _(IG) QAM-16 4 2 NUC-16 44 NUQ-64 6 3 NUC-64 6 6 NUQ-256 8 4 NUC-256 8 8 NUQ-1024 10 5 NUC-102410 10

The inner-group interleaving process is performed with N Q_(QCB) _(_)_(IG) QC blocks of the QCB interleaving output Inner-group interleavinghas a process of writing and reading the bits of the inner-group using360 columns and N Q_(QCB) _(_) _(IG) rows. In the write operation, thebits from the QCB interleaving output are written row-wise. The readoperation is performed column-wise to read out m bits from each row,where m is equal to 1 for NUC and 2 for NUQ.

FIG. 24 illustrates a cell-word demultiplexing according to anembodiment of the present invention.

(a) shows a cell-word demultiplexing for 8 and 12 bpcu MIMO and (b)shows a cell-word demultiplexing for 10 bpcu MIMO.

Each cell word (c_(0,1), c_(1,1), . . . , c_(nmod-1,1)) of the bitinterleaving output is demultiplexed into (d_(1,0,m), d_(1,1,m), . . . ,d_(1,nmod-1,m)) and (d_(2,0,m), d_(2,1,m), . . . , d_(2,nmod-1,m)) asshown in (a), which describes the cell-word demultiplexing process forone XFECBLOCK.

For the 10 bpcu MIMO case using different types of NUQ for MIMOencoding, the Bit Interleaver for NUQ-1024 is re-used. Each cell word(c_(0,1), c_(1,1), . . . , c_(9,1)) of the Bit Interleaver output isdemultiplexed into (d_(1,0,m), d_(1,1, m) . . . , d_(1,3,m)) and(d_(2,0,m), d_(2,1,m) . . . , d_(2,5,m)), as shown in (b).

FIG. 25 illustrates a time interleaving according to an embodiment ofthe present invention.

(a) to (c) show examples of TI mode.

The time interleaver operates at the DP level. The parameters of timeinterleaving (TI) may be set differently for each DP.

The following parameters, which appear in part of the PLS2-STAT data,configure the TI:

DP_TI_TYPE (allowed values: 0 or 1): Represents the TI mode; ‘0’indicates the mode with multiple TI blocks (more than one TI block) perTI group. In this case, one TI group is directly mapped to one frame (nointer-frame interleaving). ‘1’ indicates the mode with only one TI blockper TI group. In this case, the TI block may be spread over more thanone frame (inter-frame interleaving).

DP_TI_LENGTH: If DP_TI_TYPE=‘0’, this parameter is the number of TIblocks N_(TI) per TI group. For DP_TI_TYPE=‘1’, this parameter is thenumber of frames P₁ spread from one TI group.

DP_NUM_BLOCK_MAX (allowed values: 0 to 1023): Represents the maximumnumber of XFECBLOCKs per TI group.

DP_FRAME_INTERVAL (allowed values: 1, 2, 4, 8): Represents the number ofthe frames I_(JUMP) between two successive frames carrying the same DPof a given PHY profile.

DP_TI_BYPASS (allowed values: 0 or 1): If time interleaving is not usedfor a DP, this parameter is set to ‘1’. It is set to ‘0’ if timeinterleaving is used.

Additionally, the parameter DP_NUM_BLOCK from the PLS2-DYN data is usedto represent the number of XFECBLOCKs carried by one TI group of the DP.

When time interleaving is not used for a DP, the following TI group,time interleaving operation, and TI mode are not considered. However,the Delay Compensation block for the dynamic configuration informationfrom the scheduler will still be required. In each DP, the XFECBLOCKsreceived from the SSD/MIMO encoding are grouped into TI groups. That is,each TI group is a set of an integer number of XFECBLOCKs and willcontain a dynamically variable number of XFECBLOCKs. The number ofXFECBLOCKs in the TI group of index n is denoted by N_(xBLOCK) _(_)_(Group)(n) and is signaled as DP_NUM_BLOCK in the PLS2-DYN data. Notethat N_(xBLOCK) _(_) _(Group)(n) may vary from the minimum value of 0 tothe maximum value N_(xBLOCK) _(_) _(Group) _(_) _(MAX) (corresponding toDP_NUM_BLOCK_MAX) of which the largest value is 1023.

Each TI group is either mapped directly onto one frame or spread overP_(I) frames.

Each TI group is also divided into more than one TI blocks (N_(TI)),where each TI block corresponds to one usage of time interleaver memory.The TI blocks within the TI group may contain slightly different numbersof XFECBLOCKs. If the TI group is divided into multiple TI blocks, it isdirectly mapped to only one frame. There are three options for timeinterleaving (except the extra option of skipping the time interleaving)as shown in the below table 33.

TABLE 33 Modes Descriptions Option-1 Each TI group contains one TI blockand is mapped directly to one frame as shown in (a). This option issignaled in the PLS2-STAT by DP_TI_TYPE = ‘0’ and DP_TI_LENGTH =‘1’(N_(TI) = 1). Option-2 Each TI group contains one TI block and ismapped to more than one frame. (b) shows an example, where one TI groupis mapped to two frames, i.e., DP_TI_LENGTH = ‘2’ (P_(I) = 2) andDP_FRAME_INTERVAL (I_(JUMP) = 2). This provides greater time diversityfor low data-rate services. This option is signaled in the PLS2-STAT byDP_TI_TYPE = ‘1’. Option-3 Each TI group is divided into multiple TIblocks and is mapped directly to one frame as shown in (c). Each TIblock may use full TI memory, so as to provide the maximum bit-rate fora DP. This option is signaled in the PLS2-STAT signaling by DP_TI_TYPE =‘0’ and DP_TI_LENGTH = N_(TI), while P_(I) = 1.

FIG. 26 shows a parity check matrix of a QC-IRA (quasi-cyclic irregularrepeat accumulate) LDPC code.

The above-described LDPC encoder may encode a parity of an LDPC encodingblock using the parity check matrix.

The parity check matrix according to the present invention is a paritycheck matrix of the QC-IRA LDPC code and may have the form of aquasi-cyclic matrix called an H matrix and be represented as H_(qc).

(a) shows a parity check matrix according to an embodiment of thepresent invention.

As shown in (a), the parity check matrix is a matrix having a horizontalsize of Q×(K+M) and a vertical size of Q×M and may include aninformation part and a parity part. The information part may include amatrix having a horizontal size of Q×K and a vertical size of Q×M andthe parity part may include a matrix having a horizontal size of Q×M anda vertical size of Q×M. In this case, an LDPC code rate corresponds toK/(K+M).

The parity check matrix according to an embodiment of the presentinvention may include randomly distributed 1s and 0s and 1 may bereferred to as an “edge”. The position of 1 in the parity check matrix,that is, the position of each edge may be represented in the form of acirculant shifted identity matrix per submatrix having a horizontal sizeof Q and a vertical size of Q. That is, a submatrix can be representedas a Q×Q circulant-shifted identity matrix including only 1 and 0.Specifically, the submatrix according to an embodiment of the presentinvention is represented as identity matrices L including I₀, I₁, I₂,{hacek over ( )}I₁ . . . , which have different positions of 1saccording to the number of circulant shifts. The number of submatricesaccording to an embodiment of the present invention may be (K+M)×M.

(b) shows the circulant-shifted identity matrices I, which representsubmatrices according to an embodiment of the present invention.

The subscript x of I_(x) indicates the number of left-circulant shiftsof columns of a circulant-shifted identity matrix. That is, I₁represents an identify matrix in which columns are circulant-shifted tothe left once and I₂ represents an identity matrix in which columns arecirculant-shifted to the left twice. I_(Q) which is an identity matrixcirculant-shifted Q times corresponding to the total number of columns,Q, may be the same matrix as I₀ due to circulant characteristic thereof.

I₀₊₂ represents a submatrix corresponding to a combination of twocirculant-shifted identity matrices. In this case, the submatrixcorresponds to a combination of the identity matrix I₀ and an identitymatrix circulant-shifted twice.

{hacek over ( )}I₁ represents a circulant-shifted identity matrix inwhich the edge of the last column of the corresponding submatrix, thatis, 1 has been removed while corresponding to the submatrix

The parity part of the parity check matrix of the QC-IRA LDPC code mayinclude only submatrices I₀ and {hacek over ( )}I₁ and the position ofsubmatrices I₀ may be fixed. As shown in (a), submatrices I₀ may bedistributed in a diagonal direction in the parity part.

An edge in the parity check matrix represents that the corresponding row(checksum node) and the corresponding column (variable node) arephysically connected. In this case, the number of 1s included in eachcolumn (variable node) may be referred to as a degree and columns mayhave the same degree or different degrees. Accordingly, the number,positions and value x of identity matrices L that represent edgesgrouped per submatrix are important factors in determining QC-IRA LDPCencoding performance and unique values may be determined per code rate.

(c) shows a base matrix of the parity check matrix according to anembodiment of the present invention. The base matrix represents only thenumber and positions of identity matrices L as specific numbers,ignoring the value x of L. As shown in (c), a base matrix may have ahorizontal size of K+M and a vertical size of M and be represented asH_(base). When L is not a matrix corresponding to a combination ofsubmatrices, the position of the corresponding submatrix may berepresented as 1. When a submatrix is represented as I₀₊₂, thissubmatrix is a matrix corresponding to a combination of twocirculant-shifted identity matrices and thus the submatrix needs to bediscriminated from a submatrix represented as one circulant-shiftedidentity matrix. In this case, the position of the submatrix may berepresented as 2 which is the number of the combined circulant-shiftedidentity matrices. In the same manner, the position of a submatrixcorresponding to a combination of N circulant-shifted identity matricescan be represented as N.

FIG. 27 shows a process of encoding the QC-IRA LDPC code according to anembodiment of the present invention.

The QC-IRA LDPC code may be encoded per submatrix, distinguished fromconventional sequential encoding, to reduce processing complexity.

(a) shows arrangement of a QC-IRA parity check matrix in a QC form. TheQC-IRA parity check matrix may be divided into 6 regions A, B, C, D, Eand T when arranged in the QC form. When a Q×K information vector s, aparity vector p1 having a length of Q and a parity vector p2 having alength of Q×(M−1) are used, a codeword x can be represented as x={s, p1,p2}.

When the efficient encoding equation of Richardson is used, the codewordx can be obtained by directly acquiring p1 and p2 from the parity checkmatrix arranged in the QC form. The efficient encoding equation ofRichardson is as follows.

MathFigure 9

φ=ET ⁻¹ B+D

p ₁ ^(T)=φ⁻¹(−ET ⁻¹ A+C)s ^(T)

p ₂ ^(T) =−T ⁻¹(As ^(T) +Bp ₁ ^(T))  [Math. 9]

(b) shows matrices

φ

and

φ⁻¹

derived according to the efficient encoding equation.

As shown in (b), φ⁻¹

can be represented as a left low triangular (sub) matrix. The parityvector p2 can be obtained by calculating s and p1 according to theabove-described equation. When the QC-IRA parity check matrix is encodedaccording to the efficient encoding equation of Richardson, at least Qparity nodes can be simultaneously processed in parallel according tocharacteristics of a Q×Q submatrix.

FIGS. 28 to 31 illustrate a process of sequentially encoding the QC-IRALDPC code according to an embodiment of the present invention. Thissequentially encoding may correspond to the above mentioned LDPCencoding.

FIG. 28 illustrates a parity check matrix permutation process accordingto an embodiment of the present invention.

(a) shows a QC-IRA LDPC parity check matrix H₁ arranged in QC form. Asshown in (a), a parity part of the matrix H₁ may include submatricesdistributed in a stepped form, which corresponds to the above-describedQC-IRA LDPC parity check matrix. To easily perform sequential encoding,rows and columns of the matrix H₁ are moved such that the matrix H₁ ismodified into a matrix H₂ according to an embodiment of the presentinvention.

(b) shows the modified matrix H₂. As shown in (b), a parity part of thematrix H₂ may include a dual diagonal matrix. In this case, an appliedrow and column permutation equation is as follows.

MathFigure 10

r _(y)=(r _(x) mod Q)M+└r _(x) /Q┘ where r _(x)=0, 1, 2, . . . , QM−1

c _(y)={((c _(x) −QK)mod Q}M+└(c _(x) −QK)/Q┘+QK where c _(x) =QK, QK+1,. . . , Q(K+M)−1  [Math. 10]

According to the above permutation equation, the r_(x)-th row of thematrix H₁ can be moved to the r_(y)-th row of the matrix H₂ and thec_(x)-th column of the matrix H₁ can be moved to the c_(y)-th column ofthe matrix H₂. In this case, column permutation can be applied only to aparity processing period

(QK≦c _(x) ≦Q(K+M)−1)

and LDPC code characteristics can be maintained even if permutation isapplied.

FIG. 29 is a table showing addresses of parity check matrix according toan embodiment of the present invention.

The table shown in the FIG. 29 represents a parity check matrix (ormatrix H) having a codeword length of 16200 and a code rate of 11/15.The table represents addresses of 1 in the parity check matrix. In thiscase, the table according to an embodiment of the present invention canbe referred to as addresses of a parity check matrix.

In the table of (a), i indicates the blocks generated when the length ofthe matrix H or codeword by the length of a submatrix. A submatrixaccording to an embodiment of the present invention is a 360×360 matrixhaving a codeword length of 16200, and thus the number of blocks can be45 obtained by dividing 16200 by 360. The each block can be sequentiallyindicated from 0. Accordingly, i can have a value in the range of 0 to44. Also, i can indicate information bit corresponding to first columnin each block.

(b) shows the positions (or addresses) of 1s (or edges) in the firstcolumn in each block.

The matrix H can be represented as H(r,c) using all rows and columnsthereof. The following equation 11 is used to derive H(r,c).

$\begin{matrix}{{MathFigure}\mspace{14mu} 11} & \; \\{{r = {{\left\lfloor {{x\left( {i,j} \right)}/Q} \right\rfloor \times Q} + {\left( {{x\left( {i,j} \right)} + m} \right){mod}\mspace{11mu} Q}}}{{c = {{i \times Q} + m}},{{H\left( {r,c} \right)} = \left\{ \begin{matrix}{0,} & {{{if}\mspace{14mu} r} = {{0\mspace{14mu} {and}\mspace{14mu} c} = 16199}} \\{1,} & {else}\end{matrix} \right.}}} & \left\lbrack {{Math}.\mspace{14mu} 11} \right\rbrack\end{matrix}$

└x┘, the largest integer less than or equal to x

j=0, . . . length of x(i)

m=0, . . . , Q−1

Q=360

In the equation, X(i,j) represents the j-th value of the i-th line inthe table.

Specifically, x(0,0)=295, x(0,1)=364 and x(1,0)=176, which correspond tothe positions of rows having 1 (or addresses of 1) corresponding to i-thline of the matrix H. In this case, maximum values of r and c can be4319 and 16199, respectively.

The performance of the LDPC code may depend on distribution of degreesof nodes of the parity check matrix, the girth according to thepositions of 1s or edges of the parity check matrix, cyclecharacteristic, connection between check nodes and variable nodes, etc.The matrix H shown optimizes node degree distribution in the case of thecodeword of 16200, Q=360 and code rate=11/15 and optimizes the positionsof 1s or edges under the condition of optimized degree distribution, Qand code rate.

The matrix H configured according to the table has the above-describedQC-IRA LDPC structure. H_(qc) can be obtained using H(r,c) derived usingthe equation and a base matrix H_(base) can be derived from H_(qc).

In addition, the matrix H according to an embodiment of the presentinvention may include a matrix H in a different from, which has the samedegree distribution as the lengths of x(i) (or degrees of correspondingvariable nodes) of the table shown in FIG. 4. Furthermore, when atransmitter performs encoding using the corresponding matrix H, theabove-described efficient encoding for QC-IRA LDPC can be employed.

Accordingly, a transmitting side can implement an encoder having highencoding performance, low complexity and high throughput and a receivingside can perform parallel decoding up to 360 level using Q andeffectively design a receiver with high throughput using the proposedmatrix H.

The following table shows degree distribution.

TABLE 34 Variable node degree 12 3 2 (# of variable node)/Q 7 26 12

When i is 0, 1, 2, 3, 4, 5 and 6, the numbers of 1s in the 0-th block to6th block are all 12. Accordingly, when the variable node degree is 12,the number of blocks having the same degree is represented as 7. When icorresponds to 33 to 44, the numbers of 1s in the thirty-third toforty-fourth block are 2. Accordingly, when the variable node degree is2, the number of blocks having the same degree is 12. As describedabove, since the parity part of the matrix H includes only submatricesrepresented as I₀ diagonally distributed in a stepped form, the variablenode degree is always 2. Hence, blocks having a variable node degree of2 can be regarded as blocks corresponding to the parity part. The numberof actual variable nodes corresponding to each variable node degree canbe obtained by multiplying the number of blocks shown in the table by Qof the submatrix.

FIG. 30 is a table showing addresses of parity check matrix according toanother embodiment of the present invention.

The table shown in FIG. 30 shows the matrix H₂ obtained by modifying thematrix H₁.

In sequential encoding, edges used in a parity processing period aretypically represented by an equation and thus the edges can be omittedfrom the table. That is, 12 blocks having a degree of 2 corresponding tothe parity part are not represented in the table.

Since the property of the matrix is maintained even if the matrix ismodified, as described above, node degree characteristic, cycle, girth,connection between check nodes and variable nodes, etc. are maintained.Accordingly, the equal encoding performance can be obtained andsequential encoding can be performed using the matrix H₂ according tothe table.

FIG. 31 illustrates a method for sequentially encoding the QC-IRA LDPCcode according to an embodiment of the present invention.

When the parity check matrix is modified into the matrix H₂ through theabove-described permutation process, sequential encoding can beperformed through updating of each parity checksum using informationbits of a codeword and checksum updating between parity checksums.

As shown in FIG. 31, the codeword can be represented using QKinformation bits and QM parity checksums. The information bits can berepresented as i according to position and parity checksums can berepresented as p_(s).

A parity checksum update process through the information bits can berepresented by the following equation 12.

MathFigure 12

p _(w) =p _(w) ⊕i _(z)  (1)

w={v+(z mod Q)M} mod(QM)  [Math. 12](2)

where z=0, 1, 2, . . . , QK−1

Here, i_(z) represents a z-th information bit and p_(w) denotes a paritychecksum that needs to be updated using i_(z). Equation (1) representsthat parity checksum p_(w) corresponding to the w-th row is updatedthrough an XOR operation performed on the z-th information and paritychecksum p_(w). According to equation (2), the position of w iscalculated using the above-described table representing the matrix H₂.Here, v denotes a number corresponding to each row in the tablerepresenting the matrix H₂. As described above, a row in the tablerepresenting the matrix H₂ corresponds to the position of a blockgenerated when the length of the matrix H or codeword is divided by thesubmatrix length. Accordingly, the information processing period shownin FIG. 6 is divided by the submatrix length Q and then the numbers ofrows corresponding to every Q-th i are read. Upon completion of checksumupdate using the information bits of the information processing period,checksum update of the parity processing period can be performed.Checksum update of the parity processing period may be represented bythe following equation 13.

MathFigure 13

p _(s) =p _(s) ⊕p _(s-1) where s=1, 2, . . . , QM−1  [Math. 13]

When S is 0, parity checksum corresponds to parity p₀ and parity valuesfrom p₁ to p_(QM-1) can be sequentially derived through XOR operationsperformed on the parity values and parity values immediately priorthereto.

FIG. 32 illustrates an LDPC decoder according to an embodiment of thepresent invention.

The LDPC decoder 700 according to an embodiment of the present inventionmay include a variable node update block 710, a check node update block720, a barrel shift block 730 and a check sum block 740. Each block willnow be described.

The variable node block 710 may update each variable node of the matrixH using an input of the LDPC decoder and a message delivered throughedges from the check node block.

The check node block 720 may update a check node of the matrix H using amessage transmitted through edges from a variable node. A node updatealgorithm according to an embodiment of the present invention mayinclude sum product algorithm, belief-propagation algorithm, min-sumalgorithm, modified min-sum algorithm, etc. and may be changed accordingto designer. In addition, since connection between variable nodes andcheck nodes is represented in the form of a Q×Q circulant identitymatrix due to characteristics of QC-IRA LDPC, Q messages betweenvariable nodes and the check node block can be simultaneously processedin parallel. The barrel shift block 730 may control circulantconnection.

The check sum block 740 is an optional block which hard-decides adecoding message for each variable node update and performs paritychecksum operation to reduce the number of decoding iterations necessaryfor error correction. In this case, the LDPC decoder 700 according to anembodiment of the present invention can output a final LDPC decodingoutput through soft decision even if the check sum block 740hard-decides the decoding message.

FIG. 33 illustrates frame structure with EAC according to an embodimentof the present invention.

The present invention provides a fast and robust Emergency Alert System(EAS) feature that can deliver emergency alert messages without delay.

The present invention defines an Emergency Alert Channel (EAC) that candeliver the emergency alerting message, such as the Common AlertingProtocol (CAP) data, directly in the physical layer so that it can bereceived robustly by all receivers, whether fixed or mobile. EAC is asrobust as PLSC for reception under any channel conditions. Theallocation and mapping of EAC within a frame is described above.

EAC is located after the PLSC when a frame has an EAC. If the frameincludes a FIC, EAC is inserted between PLSC and FIC. EAC carries a coretext message or table such as a CAP message. In addition, EAC mayinclude information related to the core text message. EAC has flagsignals to indicate the presence of additional information and indicatewhich DP or DPs within the frame deliver additional information. Theillustration shows one example of a frame with EAC and DPs that deliveradditional information related to EAC.

EAC can carry a maximum 4 Kbytes of data including an emergency alertmessage within a frame. For more than 4 Kbytes, the emergency alertmessage can be carried through multiple frames. The content, syntax, andsemantics for EAC can be specified by the Management Layer.

The present invention provides two-step wake-up signaling to collect EASinformation through EAC. In the first step, the scrambled sequence ofthe preamble provides signaling when an emergency occurs. This timedomain sequence can wake up a receiver quickly in an emergencysituation. The preamble also carries a 1-bit flag (EAC flag) in thepreamble signaling data.

For the second step of wake-up, the system provides signalinginformation to decode

EAC in the PLS2. The PLS2 carries three types of signaling informationrelated to EAS,

1) EAC_flag: 1-bit

2) EAS_wake_up_version_num: 8-bits

3) EAC length byte: 12-bits

EAC_flag has the same value as in the preamble. TheEAS_wake_up_version_num can be used by the receiver to decide whetherEAC is new and should be decoded. The field EAC_length_byte indicatesthe length of EAC in bytes.

FIG. 34 illustrates frame structure with EAC according to an embodimentof the present invention.

The present invention provides Frame-based scheduling for the fastaccess to an emergency alert message. The preamble provides a“wake_up_indicator” to indicate when a receiver should decide whether towake up. The preamble also provides “EAC_flag” to indicate whether EACis within the current frame. The wake_up_indicator is set according tothe EAS message, and is determined independently for each broadcastchannel.

The illustration shows one example of frame-based scheduling and timingdiagram of two signals. When a receiver is in standby mode and isperiodically checking for a wake-up indication, the receiver can receiveand quickly decode the first incoming EAS data of the EAC with thepre-notification of the ‘wake_up_indication’ ahead of ‘EAC_flag’.

‘TW’ in the illustration indicates the number of the frames by which the“wake-up_indicator” of the preamble is set to ‘ON’ before ‘EAC_flag’ isset to ‘ON’. ‘TW’ is greater than or equal to zero.

The present invention provides an in-band signaling method. The‘EAC_flag’ is also carried in the in-band signaling field. When anemergency alert occurs while decoding a particular service, it can berecognized using the in-band signaling.

FIG. 35 illustrates receiver flow for responding to the wake-upindicator according to an embodiment of the present invention.

The illustration describes a mechanism by which receivers in a standbymode can react to a certain alert message via a wake-up function.Wake-up capable receivers are expected to monitor the signal from one ofthe broadcasters that have been noted to have sent emergency alertmessages via EAC.

The illustration shows an example of receiver flow for responding to thewake-up indicator while minimizing power consumption.

A receiver in standby mode detect the EAS sequence in preamble. Thereceiver search for the sequence during the maximum frame length. If thesequence is not detected, the wake-up is disabled. If the sequence isdetected, the wake-up is enabled.

If there is no EAC_flag in preamble signaling, EAC is not in the frame.In this case, the receiver wait for the next frame. The check intervalequals to minimum frame length. If there is a EAC_flag in preamblesignaling, it means that the frame has EAC. In this case, the receivergoes into the Active mode.

The receiver in the active mode decodes the PLS2. If PLS2 has noEAC_flag, it means that frame has no EAC, so the receiver will wait forthe next frame. If PLS2 has a EAC_flag, it means that frame has EAC. Inlatter case, the receiver will decode the EAC, and conduct EASprocessing.

FIG. 36 illustrates receiver flow for wake-up versioning according to anembodiment of the present invention.

When a wake-up indication has been dismissed by the user, it can bepossible for the receiver to ignore or obtain subsequent repeatedtransmission of the wake-up signal for the same emergency alert event.This can be done by checking the version number for the wake-upindication signal as described in the illustration.

The process is the same with the process of responding to the wake-upindicator, except that the receiver in active mode check version for thewake-up indication signal before decoding EAC.

The receiver check the EAS_wake_up_version_number in PLS2. If thewake-up signal is old version, the receiver will wait for the nextframe. If the wake-up signal is new version, the receiver will decodethe EAC.

FIG. 37 illustrates a method of transmitting broadcast signal accordingto an embodiment of the present invention.

The method includes encoding DP data, building at least one signal frameand/or modulating data by an OFDM method & transmitting broadcastsignals.

In step of encoding DP data, the above-described BICM module may encodeeach data pipe (DP) according to a code rate. The step of encoding DPdata can include LDPC encoding, Bit interleaving and/or mapping ontoconstellations.

The step of LDPC (Low-Density Parity-Check) encoding corresponds toabove-described LDPC encoding. The LDPC encoding is performed on the DPdata by using addresses of a parity check matrix and length of a LDPCcodeword. The addresses of the parity check matrix indicates addressesof parity bits to be calculated, and the addresses of the parity checkmatrix is defined according to the code rate.

The step of Bit interleaving corresponds to above-described Bitinterleaving by the Bit interleaver. The Bit interleaving is performedon the LDPC encoded DP data.

The step of mapping onto constellations corresponds to above-describedconstellation mapping by the constellation mapper. The mapping ontoconstellation is performed on the bit interleaved DP data.

The step of building at least one signal frame corresponds toabove-described frame building. The building signal frame is performedon the encoded DP data.

The step of modulating data by an OFDM method & transmitting broadcastsignals corresponds to above-described OFDM generation process. Thebuilt signal frame is being modulated by OFDM method, and the broadcastsignals having the modulated data are being transmitted.

In this embodiment, the signal frame includes an Emergency Alert System,EAS, information for emergency alert. The signal frame includes apreamble generated by using an EAS sequence, and the EAS sequence is tobe detected by a receiver for emergency alert.

In a method of transmitting broadcast signal according to otherembodiment of the present invention, the code rate is 11/15, and thelength of the LDPC codeword is 16200 bits.

In a method of transmitting broadcast signal according to anotherembodiment of the present invention, the parity check matrix includes aninformation part corresponding to information bits of the LDPC codewordand a parity part corresponding to the parity bits of the LDPC codeword.The addresses of the parity check matrix is expressed as follows.

TABLE 35 49 719 784 794 968 2382 2685 2873 2974 2995 3540 4179 272 281374 1279 2034 2067 2112 3429 3613 3815 3838 4216 206 714 820 1800 19252147 2168 2769 2806 3253 3415 4311 62 159 166 605 1496 1711 2652 30163347 3517 3654 4113 363 733 1118 2062 2613 2736 3143 3427 3664 4100 41574314 57 142 436 983 1364 2105 2113 3074 3639 3835 4164 4242 870 921 9501212 1861 2128 2707 2993 3730 3968 3983 4227 185 2684 3263 2035 21232913 883 2221 3521 1344 1773 4132 438 3178 3650 543 756 1639 1057 23372898 171 3298 3929 1626 2960 3503 484 3050 3323 2283 2336 4189 2732 41324318 225 2335 3497 600 2246 2658 1240 2790 3020 301 1097 3539 1222 12672594 1364 2004 3603 1142 1185 2147 564 1505 2086 697 991 2908 1467 20733462 2574 2818 3637 748 2577 2772 1151 1419 4129 164 1238 3401

In the above expression, each row represents a first information bit ineach group of 360 information bits, and each value corresponding to theeach row represents the addresses of the parity bits to be calculated.

In a method of transmitting broadcast signal according to anotherembodiment of the present invention, each of first to seventh rows has12 addresses of the parity bits, and each of eighth to thirty-third rowshas 3 addresses of the parity bits.

In a method of transmitting broadcast signal according to anotherembodiment of the present invention, the signal frame includes signalinginformation to decode the EAS information.

In a method of transmitting broadcast signal according to anotherembodiment of the present invention, the signaling information isincluded in Emergency Alert Channel, EAC, and the signal frame includesa EAC_flag indicating whether the EAC is within the signal frame.

The method of transmitting broadcast signal according to an embodimentof the present invention can be implemented in an apparatus.

The apparatus includes an encoding module, a frame building module, amodulating module and/or a transmitting module.

The encoding module is configured to encode Data Pipe, DP, dataaccording to a code rate. The encoding module corresponds toabove-described BICM module. The encoding may represents the encoding bythe above-described BICM module. The encoding module can include a LDPCencoding module, a Bit interleaving module and/or a mapping module.

The LDPC (Low-Density Parity-Check) encoding module is configured toLDPC encode the DP data using addresses of a parity check matrix andlength of a LDPC codeword. The LDPC encoding corresponds toabove-described LDPC encoding. The addresses of the parity check matrixindicates addresses of parity bits to be calculated, and the addressesof the parity check matrix is defined according to the code rate.

The Bit interleaving module is configured to bit interleave the LDPCencoded DP data. The Bit interleaving corresponds to above-described Bitinterleaving by the Bit interleaver.

The mapping module is configured to map the bit interleaved DP data ontoconstellations. The mapping onto constellations corresponds toabove-described constellation mapping by the constellation mapper.

The frame building module is configured to build at least one signalframe by mapping the encoded DP data. The building at least one signalframe corresponds to above-described frame building.

The modulating module is configured to modulate data in the built signalframe by an Orthogonal Frequency Division Multiplexing, OFDM, method.The modulating data corresponds to above-described OFDM generationprocess.

The transmitting module is configured to transmit the broadcast signalshaving the modulated data. The transmitting broadcast signalscorresponds to above-described OFDM generation process.

In this embodiment, the signal frame includes an Emergency Alert System,EAS, information for emergency alert. The signal frame includes apreamble generated by using an EAS sequence, and the EAS sequence is tobe detected by a receiver for emergency alert.

In an apparatus for transmitting broadcast signal according to otherembodiment of the present invention, the code rate is 11/15, and thelength of the LDPC codeword is 16200 bits.

In an apparatus for transmitting broadcast signal according to anotherembodiment of the present invention, the parity check matrix includes aninformation part corresponding to information bits of the LDPC codewordand a parity part corresponding to the parity bits of the LDPC codeword.The addresses of the parity check matrix is expressed as follows.

TABLE 36 49 719 784 794 968 2382 2685 2873 2974 2995 3540 4179 272 281374 1279 2034 2067 2112 3429 3613 3815 3838 4216 206 714 820 1800 19252147 2168 2769 2806 3253 3415 4311 62 159 166 605 1496 1711 2652 30163347 3517 3654 4113 363 733 1118 2062 2613 2736 3143 3427 3664 4100 41574314 57 142 436 983 1364 2105 2113 3074 3639 3835 4164 4242 870 921 9501212 1861 2128 2707 2993 3730 3968 3983 4227 185 2684 3263 2035 21232913 883 2221 3521 1344 1773 4132 438 3178 3650 543 756 1639 1057 23372898 171 3298 3929 1626 2960 3503 484 3050 3323 2283 2336 4189 2732 41324318 225 2335 3497 600 2246 2658 1240 2790 3020 301 1097 3539 1222 12672594 1364 2004 3603 1142 1185 2147 564 1505 2086 697 991 2908 1467 20733462 2574 2818 3637 748 2577 2772 1151 1419 4129 164 1238 3401

In the above expression, each row represents a first information bit ineach group of 360 information bits, and each value corresponding to theeach row represents the addresses of the parity bits to be calculated.

In an apparatus for transmitting broadcast signal according to anotherembodiment of the present invention, each of first to seventh rows has12 addresses of the parity bits, and each of eighth to thirty-third rowshas 3 addresses of the parity bits.

In an apparatus for transmitting broadcast signal according to anotherembodiment of the present invention, the signal frame includes signalinginformation to decode the EAS information.

In an apparatus for transmitting broadcast signal according to anotherembodiment of the present invention, the signaling information isincluded in Emergency Alert Channel, EAC, and the signal frame includesa EAC_flag indicating whether the EAC is within the signal frame.

In each DP, the TI memory stores the input XFECBLOCKs (output XFECBLOCKsfrom the SSD/MIMO encoding block). Assume that input XFECBLOCKs aredefined as

(d_(n, x, 0, 0), d_(n, s, 0, 1), … , d_(n, s, 0, N_(cells) − 1), d_(n, s, 1, 0), … , d_(n, s, 1, N_(cells) − 1), … , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, 0), … , d_(n, s, N_(xBLOCK_TI)(n, s) − 1, N_(cells) − 1)),

where d_(n,s,r,q) is the qth cell of the rth XFECBLOCK in the sth TIblock of the nth TI group and represents the outputs of SSD and MIMOencodings as follows.

$d_{n,s,r,q} = \left\{ \begin{matrix}{f_{n,s,r,q},} & {{the}\mspace{14mu} {outputof}\mspace{14mu} {SSD}\mspace{11mu} \ldots \mspace{14mu} {encoding}} \\{g_{n,s,r,q},} & {{theoutputof}\mspace{14mu} {MIMOencoding}}\end{matrix} \right.$

In addition, assume that output XFECBLOCKs from the time interleaver aredefined as

(h_(n, s, 0), h_(n, s, 1), … , h_(n, s, i), … , h_(n, s, N_(xBLOCK_TI)(n, s) × N_(cells) − 1)),

where h_(n,s,i) is the ith output cell (for i=0, . . . , N_(xBLOCK) _(_)_(TI)(n,s)×N_(cells)-1) in the sth TI block of the nth TI group.

Typically, the time interleaver will also act as a buffer for DP dataprior to the process of frame building. This is achieved by means of twomemory banks for each DP. The first TI-block is written to the firstbank. The second TI-block is written to the second bank while the firstbank is being read from and so on.

The TI is a twisted row-column block interleaver. For the sth TI blockof the nth TI group, the number of rows N_(r) of a TI memory is equal tothe number of cells N_(cells), i.e., N_(r)=N_(cells) while the number ofcolumns N_(c) is equal to the number N_(xBLOCK) _(_) _(TI)(n,s)

FIG. 38 illustrates the basic operation of a twisted row-column blockinterleaver according to an embodiment of the present invention.

shows a writing operation in the time interleaver and (b) shows areading operation in the time interleaver The first XFECBLOCK is writtencolumn-wise into the first column of the TI memory, and the secondXFECBLOCK is written into the next column, and so on as shown in (a).Then, in the interleaving array, cells are read out diagonal-wise.During diagonal-wise reading from the first row (rightwards along therow beginning with the left-most column) to the last row, N_(r) cellsare read out as shown in (b). In detail, assuming z_(n,s,i) (i=0, . . ., N_(r)N_(c)) as the TI memory cell position to be read sequentially,the reading process in such an interleaving array is performed bycalculating the row index R_(n,s,i) the column index C_(n,s,i) and theassociated twisting parameter T_(n,s,i) as follows expression.

$\begin{matrix}{{MathFigure}\mspace{14mu} 14} & \; \\{{{GENERATE}\mspace{11mu} \left( {R_{n,s,i},C_{n,s,i}} \right)} = \left\{ {{R_{n,s,i} = {{mod}\left( {i,N_{r}} \right)}},{T_{n,s,i} = {{mod}\left( {{S_{shift} \times R_{n,s,i}},N_{c}} \right)}},{C_{n,s,i} = {{mod}\left( {{T_{n,s,i} + \left\lfloor \frac{i}{N_{r}} \right\rfloor},N_{c}} \right)}}} \right\}} & \left\lbrack {{Math}.\mspace{14mu} 14} \right\rbrack\end{matrix}$

where

S_(shift)

is a common shift value for the diagonal-wise reading process regardlessof

N_(xBLOCK) _(_) _(TI)(n,s),

and it is determined by

N_(xBLOCK) _(_) _(TI) _(_) _(MAX)

given in the PLS2-STAT as follows expression.

MathFigure 15

                                      [Math.  15]${for}\mspace{14mu} \left\{ {\begin{matrix}{{N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}^{\prime} = {N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}} + 1}},} & {{{if}\mspace{14mu} N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}{mod}\; 2} = 0} \\{{N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}^{\prime} = N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}},} & {{{if}\mspace{14mu} N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}{mod}\; 2} = 1}\end{matrix},\mspace{20mu} {S_{shift} = \frac{N_{{xBLOCK}\; \_ \; {TI}\; \_ \; {MAX}}^{\prime} - 1}{2}}} \right.$

As a result, the cell positions to be read are calculated by acoordinate as z_(n,s,i)=N_(r)C_(n,s,i)+R_(n,s,i)

FIG. 39 illustrates an operation of a twisted row-column blockinterleaver according to another embodiment of the present invention.

More specifically, FIG. 39 illustrates the interleaving array in the TImemory for each TI group, including virtual XFECBLOCKs when

N_(xBTOCK) _(_) _(TI)(0,0)=3,N_(xBLOCK) _(_) _(TI)(1,0)=6,N_(xBLOCK) _(_) _(TI)(2,0)=5.

The variable number

N_(xBLOCK) _(_) _(TI)(n,s)=N_(r)

will be less than or equal to

N′_(xBLOCK) _(_) _(TI) _(_) _(MAX.)

Thus, in order to achieve a single-memory deinterleaving at the receiverside, regardless of

N_(xBLOCK) _(_) _(TI)(n,s),

the interleaving array for use in a twisted row-column block interleaveris set to the size of

N_(r)×N_(c)=N_(cells)×N_(xBLOCK) _(_) _(TI) _(_) _(MAX)

by inserting the virtual XFECBLOCKs into the TI memory and the readingprocess is accomplished as follow expression.

MathFigure 16

[Math. 16] p = 0; for i = 0;i < N_(cells)N′_(xBLOCK) _(—) _(TI) _(—)_(MAX);i = i + 1 {GENERATE(R_(n,s,i),C_(n,s,i)); V_(i) =N_(r)C_(n,s,j) + R_(n,s,j) if V_(i) < N_(cells)N_(xBLOCK) _(—)_(TI)(n,s) { Z_(n,s,p) = V_(i); p = p + 1; } }

The number of TI groups is set to 3. The option of time interleaver issignaled in the PLS2-STAT data by DP_TI_TYPE=‘0’, DP_FRAME_INTERVAL=‘1’,and DP_TI_LENGTH=‘1’, i.e., N_(TI)=1, I_(JUMP)=1, and P₁=1. The numberof XFECBLOCKs, each of which has N_(cells)=30 cells, per TI group issignaled in the PLS2-DYN data by N_(xBLOCK) _(_) _(TI)(0,0)=3,N_(xBLOCK) _(_) _(TI)(1,0)=6, and N_(xBLOCK) _(_) _(TI)(2,0)=5,respectively. The maximum number of XFECBLOCK is signaled in thePLS2-STAT data by N_(xBLOCK) _(_) _(Group) _(_) _(MAX), which leads to

└N_(xBLOCK) _(_) _(Group) _(—MAX) /N_(TI)┘=N_(xBLOCK) _(_) _(TI) _(—MAX)=6

FIG. 40 illustrates a diagonal-wise reading pattern of a twistedrow-column block interleaver according to an embodiment of the presentinvention.

More specifically FIG. 40 shows a diagonal-wise reading pattern fromeach interleaving array with parameters of

N′_(xBLOCK TI MAX)=7

and S_(Shift)=(7−1)/2=3. Note that in the reading process shown aspseudocode above, if v_(i)≧_(cells)N_(xBLOCK TI)(n,s),

the value of V, is skipped and the next calculated value of V, is used.

FIG. 41 illustrates interlaved XFECBLOCKs from each interleaving arrayaccording to an embodiment of the present invention.

FIG. 41 illustrates the interleaved XFECBLOCKs from each interleavingarray with parameters of

N′_(xBLOCK) _(_) _(TI) _(—MAX) =7

and S_(shift)=3.

Another embodiments of the present invention will be described below.These embodiments are based on each code rate. Each embodiments arebased on a codeword length of 16200. For each embodiments, the H₁matrixes, H₂ matrixes and degree distribution tables will be described.Each of the H₁ matrixes, H₂ matrixes and degree distribution tables havedifferent values depends on each code rates. But the structures anddescriptions are the same as the H₁ matrix, H₂ matrix and degreedistribution table, described above.

One of the embodiments according to a code rate of 11/15 will bedescribed below.

FIG. 42 illustrates one of the embodiments of the H₁ matrix according toa code rate of 11/15.

FIG. 43 illustrates one of the embodiments of the H₂ matrix according toa code rate of 11/15.

FIG. 44 illustrates one of the embodiments of the degree distributiontable according to a code rate of 11/15.

Although the description of the present invention is explained withreference to each of the accompanying drawings for clarity, it ispossible to design new embodiment(s) by merging the embodiments shown inthe accompanying drawings with each other. And, if a recording mediumreadable by a computer, in which programs for executing the embodimentsmentioned in the foregoing description are recorded, is designed innecessity of those skilled in the art, it may belong to the scope of theappended claims and their equivalents.

An apparatus and method according to the present invention may benon-limited by the configurations and methods of the embodimentsmentioned in the foregoing description. And, the embodiments mentionedin the foregoing description can be configured in a manner of beingselectively combined with one another entirely or in part to enablevarious modifications.

In addition, a method according to the present invention can beimplemented with processor-readable codes in a processor-readablerecording medium provided to a network device. The processor-readablemedium may include all kinds of recording devices capable of storingdata readable by a processor. The processor-readable medium may includeone of ROM, RAM, CD-ROM, magnetic tapes, floppy discs, optical datastorage devices, and the like for example and also include such acarrier-wave type implementation as a transmission via Internet.Furthermore, as the processor-readable recording medium is distributedto a computer system connected via network, processor-readable codes canbe saved and executed according to a distributive system.

It will be appreciated by those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

Both apparatus and method inventions are mentioned in this specificationand descriptions of both of the apparatus and method inventions may becomplementarily applicable to each other.

MODE FOR THE INVENTION

Various embodiments have been described in the best mode for carryingout the invention.

INDUSTRIAL APPLICABILITY

The present invention is available in a series of broadcast signalprovision fields.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. An apparatus for transmitting broadcast signals, the apparatuscomprising: an encoder to encode Data Pipe (DP) data according to a coderate; a frame builder to build at least one signal frame by mapping theencoded DP data; a modulator to modulate data in the built signal frameby an Orthogonal Frequency Division Multiplexing (OFDM) method; apreamble inserter to insert a preamble at a beginning of each signalframe in a time domain; and a transmitter to transmit the broadcastsignals having the modulated data.
 2. The apparatus of claim 1, whereinthe preamble includes an Emergency Alert System (EAS) information foremergency alert.
 3. The apparatus of claim 1, wherein the encoderencodes the DP data according to the code rate and a codeword, whereinthe codeword has information bits and parity bits, and wherein theparity bits are calculated using the information bits based on addressesof a parity check matrix.
 4. The apparatus of claim 3, wherein a lengthof the codeword is 16200 bits and the code rate is 11/15.
 5. Theapparatus of claim 4, wherein the addresses of the parity check matrixare expressed as:49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401 wherein each row representseach group of 360 information bits, and wherein each value correspondingto the each row represents the addresses of the parity bits to becalculated.
 6. An apparatus for receiving broadcast signals, theapparatus comprising: a receiver to receive broadcast signals havingmodulated data in signal frames; a de-modulator to de-modulate themodulated data by an Orthogonal Frequency Division Multiplexing (OFDM)method; a parser to parse at least one signal frame by de-mapping DataPipe (DP) data; and a decoder to decode the DP data according to a coderate.
 7. The apparatus of claim 6, wherein the preamble includes anEmergency Alert System (EAS) information for emergency alert.
 8. Theapparatus of claim 6, wherein the decoder decodes the DP data accordingto the code rate and a codeword, wherein the codeword has informationbits and parity bits, and wherein the parity bits are calculated usingthe information bits based on addresses of a parity check matrix.
 9. Theapparatus of claim 8, wherein a length of the codeword is 16200 bits andthe code rate is 11/15.
 10. The apparatus of claim 9, wherein theaddresses of the parity check matrix are expressed as:49  719  784  794  968  2382  2685  2873  2974  2995  3540  4179272  281  374  1279  2034  2067  2112  3429  3613  3815  3838  4216206  714  820  1800  1925  2147  2168  2769  2806  3253  3415  431162  159  166  605  1496  1711  2652  3016  3347  3517  3654  4113363  733  1118  2062  2613  2736  3143  3427  3664  4100  4157  431457  142  436  983  1364  2105  2113  3074  3639  3835  4164  4242870  921  950  1212  1861  2128  2707  2993  3730  3968  3983  4227185  2684  3263 2035  2123  2913 883  2221  35211344  1773  4132 438  3178  3650 543  756  16391057  2337  2898 171  3298  3929 1626  2960  3503484  3050  3323 2283  2336  4189 2732  4132  4318225  2335  3497 600  2246  2658 1240  2790  3020301  1097  3539 1222  1267  2594 1364  2004  36031142  1185  2147 564  1505  2086 697  991  29081467  2073  3462 2574  2818  3637 748  2577  27721151  1419  4129 164  1238  3401, wherein each row representseach group of 360 information bits, and wherein each value correspondingto the each row represents the addresses of the parity bits to becalculated.